This commit is contained in:
krahets
2023-10-06 14:10:18 +08:00
parent dda64b52e1
commit 3d2d669b43
51 changed files with 38928 additions and 1994 deletions

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@@ -43,61 +43,210 @@ $$
=== "Python"
```python title="min_cost_climbing_stairs_dp.py"
[class]{}-[func]{min_cost_climbing_stairs_dp}
def min_cost_climbing_stairs_dp(cost: list[int]) -> int:
"""爬楼梯最小代价:动态规划"""
n = len(cost) - 1
if n == 1 or n == 2:
return cost[n]
# 初始化 dp 表,用于存储子问题的解
dp = [0] * (n + 1)
# 初始状态:预设最小子问题的解
dp[1], dp[2] = cost[1], cost[2]
# 状态转移:从较小子问题逐步求解较大子问题
for i in range(3, n + 1):
dp[i] = min(dp[i - 1], dp[i - 2]) + cost[i]
return dp[n]
```
=== "C++"
```cpp title="min_cost_climbing_stairs_dp.cpp"
[class]{}-[func]{minCostClimbingStairsDP}
/* 爬楼梯最小代价:动态规划 */
int minCostClimbingStairsDP(vector<int> &cost) {
int n = cost.size() - 1;
if (n == 1 || n == 2)
return cost[n];
// 初始化 dp 表,用于存储子问题的解
vector<int> dp(n + 1);
// 初始状态:预设最小子问题的解
dp[1] = cost[1];
dp[2] = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for (int i = 3; i <= n; i++) {
dp[i] = min(dp[i - 1], dp[i - 2]) + cost[i];
}
return dp[n];
}
```
=== "Java"
```java title="min_cost_climbing_stairs_dp.java"
[class]{min_cost_climbing_stairs_dp}-[func]{minCostClimbingStairsDP}
/* 爬楼梯最小代价:动态规划 */
int minCostClimbingStairsDP(int[] cost) {
int n = cost.length - 1;
if (n == 1 || n == 2)
return cost[n];
// 初始化 dp 表,用于存储子问题的解
int[] dp = new int[n + 1];
// 初始状态:预设最小子问题的解
dp[1] = cost[1];
dp[2] = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for (int i = 3; i <= n; i++) {
dp[i] = Math.min(dp[i - 1], dp[i - 2]) + cost[i];
}
return dp[n];
}
```
=== "C#"
```csharp title="min_cost_climbing_stairs_dp.cs"
[class]{min_cost_climbing_stairs_dp}-[func]{minCostClimbingStairsDP}
/* 爬楼梯最小代价:动态规划 */
int minCostClimbingStairsDP(int[] cost) {
int n = cost.Length - 1;
if (n == 1 || n == 2)
return cost[n];
// 初始化 dp 表,用于存储子问题的解
int[] dp = new int[n + 1];
// 初始状态:预设最小子问题的解
dp[1] = cost[1];
dp[2] = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for (int i = 3; i <= n; i++) {
dp[i] = Math.Min(dp[i - 1], dp[i - 2]) + cost[i];
}
return dp[n];
}
```
=== "Go"
```go title="min_cost_climbing_stairs_dp.go"
[class]{}-[func]{minCostClimbingStairsDP}
/* 爬楼梯最小代价:动态规划 */
func minCostClimbingStairsDP(cost []int) int {
n := len(cost) - 1
if n == 1 || n == 2 {
return cost[n]
}
// 初始化 dp 表,用于存储子问题的解
dp := make([]int, n+1)
// 初始状态:预设最小子问题的解
dp[1] = cost[1]
dp[2] = cost[2]
// 状态转移:从较小子问题逐步求解较大子问题
for i := 3; i <= n; i++ {
dp[i] = int(math.Min(float64(dp[i-1]), float64(dp[i-2]+cost[i])))
}
return dp[n]
}
```
=== "Swift"
```swift title="min_cost_climbing_stairs_dp.swift"
[class]{}-[func]{minCostClimbingStairsDP}
/* 爬楼梯最小代价:动态规划 */
func minCostClimbingStairsDP(cost: [Int]) -> Int {
let n = cost.count - 1
if n == 1 || n == 2 {
return cost[n]
}
// 初始化 dp 表,用于存储子问题的解
var dp = Array(repeating: 0, count: n + 1)
// 初始状态:预设最小子问题的解
dp[1] = cost[1]
dp[2] = cost[2]
// 状态转移:从较小子问题逐步求解较大子问题
for i in stride(from: 3, through: n, by: 1) {
dp[i] = min(dp[i - 1], dp[i - 2]) + cost[i]
}
return dp[n]
}
```
=== "JS"
```javascript title="min_cost_climbing_stairs_dp.js"
[class]{}-[func]{minCostClimbingStairsDP}
/* 爬楼梯最小代价:动态规划 */
function minCostClimbingStairsDP(cost) {
const n = cost.length - 1;
if (n === 1 || n === 2) {
return cost[n];
}
// 初始化 dp 表,用于存储子问题的解
const dp = new Array(n + 1);
// 初始状态:预设最小子问题的解
dp[1] = cost[1];
dp[2] = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for (let i = 3; i <= n; i++) {
dp[i] = Math.min(dp[i - 1], dp[i - 2]) + cost[i];
}
return dp[n];
}
```
=== "TS"
```typescript title="min_cost_climbing_stairs_dp.ts"
[class]{}-[func]{minCostClimbingStairsDP}
/* 爬楼梯最小代价:动态规划 */
function minCostClimbingStairsDP(cost: Array<number>): number {
const n = cost.length - 1;
if (n === 1 || n === 2) {
return cost[n];
}
// 初始化 dp 表,用于存储子问题的解
const dp = new Array(n + 1);
// 初始状态:预设最小子问题的解
dp[1] = cost[1];
dp[2] = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for (let i = 3; i <= n; i++) {
dp[i] = Math.min(dp[i - 1], dp[i - 2]) + cost[i];
}
return dp[n];
}
```
=== "Dart"
```dart title="min_cost_climbing_stairs_dp.dart"
[class]{}-[func]{minCostClimbingStairsDP}
/* 爬楼梯最小代价:动态规划 */
int minCostClimbingStairsDP(List<int> cost) {
int n = cost.length - 1;
if (n == 1 || n == 2) return cost[n];
// 初始化 dp 表,用于存储子问题的解
List<int> dp = List.filled(n + 1, 0);
// 初始状态:预设最小子问题的解
dp[1] = cost[1];
dp[2] = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for (int i = 3; i <= n; i++) {
dp[i] = min(dp[i - 1], dp[i - 2]) + cost[i];
}
return dp[n];
}
```
=== "Rust"
```rust title="min_cost_climbing_stairs_dp.rs"
[class]{}-[func]{min_cost_climbing_stairs_dp}
/* 爬楼梯最小代价:动态规划 */
fn min_cost_climbing_stairs_dp(cost: &[i32]) -> i32 {
let n = cost.len() - 1;
if n == 1 || n == 2 { return cost[n]; }
// 初始化 dp 表,用于存储子问题的解
let mut dp = vec![-1; n + 1];
// 初始状态:预设最小子问题的解
dp[1] = cost[1];
dp[2] = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for i in 3..=n {
dp[i] = cmp::min(dp[i - 1], dp[i - 2]) + cost[i];
}
dp[n]
}
```
=== "C"
@@ -109,7 +258,23 @@ $$
=== "Zig"
```zig title="min_cost_climbing_stairs_dp.zig"
[class]{}-[func]{minCostClimbingStairsDP}
// 爬楼梯最小代价:动态规划
fn minCostClimbingStairsDP(comptime cost: []i32) i32 {
comptime var n = cost.len - 1;
if (n == 1 or n == 2) {
return cost[n];
}
// 初始化 dp 表,用于存储子问题的解
var dp = [_]i32{-1} ** (n + 1);
// 初始状态:预设最小子问题的解
dp[1] = cost[1];
dp[2] = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for (3..n + 1) |i| {
dp[i] = @min(dp[i - 1], dp[i - 2]) + cost[i];
}
return dp[n];
}
```
图 14-7 展示了以上代码的动态规划过程。
@@ -123,61 +288,181 @@ $$
=== "Python"
```python title="min_cost_climbing_stairs_dp.py"
[class]{}-[func]{min_cost_climbing_stairs_dp_comp}
def min_cost_climbing_stairs_dp_comp(cost: list[int]) -> int:
"""爬楼梯最小代价:空间优化后的动态规划"""
n = len(cost) - 1
if n == 1 or n == 2:
return cost[n]
a, b = cost[1], cost[2]
for i in range(3, n + 1):
a, b = b, min(a, b) + cost[i]
return b
```
=== "C++"
```cpp title="min_cost_climbing_stairs_dp.cpp"
[class]{}-[func]{minCostClimbingStairsDPComp}
/* 爬楼梯最小代价:空间优化后的动态规划 */
int minCostClimbingStairsDPComp(vector<int> &cost) {
int n = cost.size() - 1;
if (n == 1 || n == 2)
return cost[n];
int a = cost[1], b = cost[2];
for (int i = 3; i <= n; i++) {
int tmp = b;
b = min(a, tmp) + cost[i];
a = tmp;
}
return b;
}
```
=== "Java"
```java title="min_cost_climbing_stairs_dp.java"
[class]{min_cost_climbing_stairs_dp}-[func]{minCostClimbingStairsDPComp}
/* 爬楼梯最小代价:空间优化后的动态规划 */
int minCostClimbingStairsDPComp(int[] cost) {
int n = cost.length - 1;
if (n == 1 || n == 2)
return cost[n];
int a = cost[1], b = cost[2];
for (int i = 3; i <= n; i++) {
int tmp = b;
b = Math.min(a, tmp) + cost[i];
a = tmp;
}
return b;
}
```
=== "C#"
```csharp title="min_cost_climbing_stairs_dp.cs"
[class]{min_cost_climbing_stairs_dp}-[func]{minCostClimbingStairsDPComp}
/* 爬楼梯最小代价:空间优化后的动态规划 */
int minCostClimbingStairsDPComp(int[] cost) {
int n = cost.Length - 1;
if (n == 1 || n == 2)
return cost[n];
int a = cost[1], b = cost[2];
for (int i = 3; i <= n; i++) {
int tmp = b;
b = Math.Min(a, tmp) + cost[i];
a = tmp;
}
return b;
}
```
=== "Go"
```go title="min_cost_climbing_stairs_dp.go"
[class]{}-[func]{minCostClimbingStairsDPComp}
/* 爬楼梯最小代价:空间优化后的动态规划 */
func minCostClimbingStairsDPComp(cost []int) int {
n := len(cost) - 1
if n == 1 || n == 2 {
return cost[n]
}
// 初始状态:预设最小子问题的解
a, b := cost[1], cost[2]
// 状态转移:从较小子问题逐步求解较大子问题
for i := 3; i <= n; i++ {
tmp := b
b = int(math.Min(float64(a), float64(tmp+cost[i])))
a = tmp
}
return b
}
```
=== "Swift"
```swift title="min_cost_climbing_stairs_dp.swift"
[class]{}-[func]{minCostClimbingStairsDPComp}
/* 爬楼梯最小代价:空间优化后的动态规划 */
func minCostClimbingStairsDPComp(cost: [Int]) -> Int {
let n = cost.count - 1
if n == 1 || n == 2 {
return cost[n]
}
var (a, b) = (cost[1], cost[2])
for i in stride(from: 3, through: n, by: 1) {
(a, b) = (b, min(a, b) + cost[i])
}
return b
}
```
=== "JS"
```javascript title="min_cost_climbing_stairs_dp.js"
[class]{}-[func]{minCostClimbingStairsDPComp}
/* 爬楼梯最小代价:状态压缩后的动态规划 */
function minCostClimbingStairsDPComp(cost) {
const n = cost.length - 1;
if (n === 1 || n === 2) {
return cost[n];
}
let a = cost[1],
b = cost[2];
for (let i = 3; i <= n; i++) {
const tmp = b;
b = Math.min(a, tmp) + cost[i];
a = tmp;
}
return b;
}
```
=== "TS"
```typescript title="min_cost_climbing_stairs_dp.ts"
[class]{}-[func]{minCostClimbingStairsDPComp}
/* 爬楼梯最小代价:状态压缩后的动态规划 */
function minCostClimbingStairsDPComp(cost: Array<number>): number {
const n = cost.length - 1;
if (n === 1 || n === 2) {
return cost[n];
}
let a = cost[1],
b = cost[2];
for (let i = 3; i <= n; i++) {
const tmp = b;
b = Math.min(a, tmp) + cost[i];
a = tmp;
}
return b;
}
```
=== "Dart"
```dart title="min_cost_climbing_stairs_dp.dart"
[class]{}-[func]{minCostClimbingStairsDPComp}
/* 爬楼梯最小代价:空间优化后的动态规划 */
int minCostClimbingStairsDPComp(List<int> cost) {
int n = cost.length - 1;
if (n == 1 || n == 2) return cost[n];
int a = cost[1], b = cost[2];
for (int i = 3; i <= n; i++) {
int tmp = b;
b = min(a, tmp) + cost[i];
a = tmp;
}
return b;
}
```
=== "Rust"
```rust title="min_cost_climbing_stairs_dp.rs"
[class]{}-[func]{min_cost_climbing_stairs_dp_comp}
/* 爬楼梯最小代价:空间优化后的动态规划 */
fn min_cost_climbing_stairs_dp_comp(cost: &[i32]) -> i32 {
let n = cost.len() - 1;
if n == 1 || n == 2 { return cost[n] };
let (mut a, mut b) = (cost[1], cost[2]);
for i in 3..=n {
let tmp = b;
b = cmp::min(a, tmp) + cost[i];
a = tmp;
}
b
}
```
=== "C"
@@ -189,7 +474,22 @@ $$
=== "Zig"
```zig title="min_cost_climbing_stairs_dp.zig"
[class]{}-[func]{minCostClimbingStairsDPComp}
// 爬楼梯最小代价:空间优化后的动态规划
fn minCostClimbingStairsDPComp(cost: []i32) i32 {
var n = cost.len - 1;
if (n == 1 or n == 2) {
return cost[n];
}
var a = cost[1];
var b = cost[2];
// 状态转移:从较小子问题逐步求解较大子问题
for (3..n + 1) |i| {
var tmp = b;
b = @min(a, tmp) + cost[i];
a = tmp;
}
return b;
}
```
## 14.2.2 &nbsp; 无后效性
@@ -237,61 +537,234 @@ $$
=== "Python"
```python title="climbing_stairs_constraint_dp.py"
[class]{}-[func]{climbing_stairs_constraint_dp}
def climbing_stairs_constraint_dp(n: int) -> int:
"""带约束爬楼梯:动态规划"""
if n == 1 or n == 2:
return 1
# 初始化 dp 表,用于存储子问题的解
dp = [[0] * 3 for _ in range(n + 1)]
# 初始状态:预设最小子问题的解
dp[1][1], dp[1][2] = 1, 0
dp[2][1], dp[2][2] = 0, 1
# 状态转移:从较小子问题逐步求解较大子问题
for i in range(3, n + 1):
dp[i][1] = dp[i - 1][2]
dp[i][2] = dp[i - 2][1] + dp[i - 2][2]
return dp[n][1] + dp[n][2]
```
=== "C++"
```cpp title="climbing_stairs_constraint_dp.cpp"
[class]{}-[func]{climbingStairsConstraintDP}
/* 带约束爬楼梯:动态规划 */
int climbingStairsConstraintDP(int n) {
if (n == 1 || n == 2) {
return 1;
}
// 初始化 dp 表,用于存储子问题的解
vector<vector<int>> dp(n + 1, vector<int>(3, 0));
// 初始状态:预设最小子问题的解
dp[1][1] = 1;
dp[1][2] = 0;
dp[2][1] = 0;
dp[2][2] = 1;
// 状态转移:从较小子问题逐步求解较大子问题
for (int i = 3; i <= n; i++) {
dp[i][1] = dp[i - 1][2];
dp[i][2] = dp[i - 2][1] + dp[i - 2][2];
}
return dp[n][1] + dp[n][2];
}
```
=== "Java"
```java title="climbing_stairs_constraint_dp.java"
[class]{climbing_stairs_constraint_dp}-[func]{climbingStairsConstraintDP}
/* 带约束爬楼梯:动态规划 */
int climbingStairsConstraintDP(int n) {
if (n == 1 || n == 2) {
return 1;
}
// 初始化 dp 表,用于存储子问题的解
int[][] dp = new int[n + 1][3];
// 初始状态:预设最小子问题的解
dp[1][1] = 1;
dp[1][2] = 0;
dp[2][1] = 0;
dp[2][2] = 1;
// 状态转移:从较小子问题逐步求解较大子问题
for (int i = 3; i <= n; i++) {
dp[i][1] = dp[i - 1][2];
dp[i][2] = dp[i - 2][1] + dp[i - 2][2];
}
return dp[n][1] + dp[n][2];
}
```
=== "C#"
```csharp title="climbing_stairs_constraint_dp.cs"
[class]{climbing_stairs_constraint_dp}-[func]{climbingStairsConstraintDP}
/* 带约束爬楼梯:动态规划 */
int climbingStairsConstraintDP(int n) {
if (n == 1 || n == 2) {
return 1;
}
// 初始化 dp 表,用于存储子问题的解
int[,] dp = new int[n + 1, 3];
// 初始状态:预设最小子问题的解
dp[1, 1] = 1;
dp[1, 2] = 0;
dp[2, 1] = 0;
dp[2, 2] = 1;
// 状态转移:从较小子问题逐步求解较大子问题
for (int i = 3; i <= n; i++) {
dp[i, 1] = dp[i - 1, 2];
dp[i, 2] = dp[i - 2, 1] + dp[i - 2, 2];
}
return dp[n, 1] + dp[n, 2];
}
```
=== "Go"
```go title="climbing_stairs_constraint_dp.go"
[class]{}-[func]{climbingStairsConstraintDP}
/* 带约束爬楼梯:动态规划 */
func climbingStairsConstraintDP(n int) int {
if n == 1 || n == 2 {
return 1
}
// 初始化 dp 表,用于存储子问题的解
dp := make([][3]int, n+1)
// 初始状态:预设最小子问题的解
dp[1][1] = 1
dp[1][2] = 0
dp[2][1] = 0
dp[2][2] = 1
// 状态转移:从较小子问题逐步求解较大子问题
for i := 3; i <= n; i++ {
dp[i][1] = dp[i-1][2]
dp[i][2] = dp[i-2][1] + dp[i-2][2]
}
return dp[n][1] + dp[n][2]
}
```
=== "Swift"
```swift title="climbing_stairs_constraint_dp.swift"
[class]{}-[func]{climbingStairsConstraintDP}
/* 带约束爬楼梯:动态规划 */
func climbingStairsConstraintDP(n: Int) -> Int {
if n == 1 || n == 2 {
return 1
}
// 初始化 dp 表,用于存储子问题的解
var dp = Array(repeating: Array(repeating: 0, count: 3), count: n + 1)
// 初始状态:预设最小子问题的解
dp[1][1] = 1
dp[1][2] = 0
dp[2][1] = 0
dp[2][2] = 1
// 状态转移:从较小子问题逐步求解较大子问题
for i in stride(from: 3, through: n, by: 1) {
dp[i][1] = dp[i - 1][2]
dp[i][2] = dp[i - 2][1] + dp[i - 2][2]
}
return dp[n][1] + dp[n][2]
}
```
=== "JS"
```javascript title="climbing_stairs_constraint_dp.js"
[class]{}-[func]{climbingStairsConstraintDP}
/* 带约束爬楼梯:动态规划 */
function climbingStairsConstraintDP(n) {
if (n === 1 || n === 2) {
return 1;
}
// 初始化 dp 表,用于存储子问题的解
const dp = Array.from(new Array(n + 1), () => new Array(3));
// 初始状态:预设最小子问题的解
dp[1][1] = 1;
dp[1][2] = 0;
dp[2][1] = 0;
dp[2][2] = 1;
// 状态转移:从较小子问题逐步求解较大子问题
for (let i = 3; i <= n; i++) {
dp[i][1] = dp[i - 1][2];
dp[i][2] = dp[i - 2][1] + dp[i - 2][2];
}
return dp[n][1] + dp[n][2];
}
```
=== "TS"
```typescript title="climbing_stairs_constraint_dp.ts"
[class]{}-[func]{climbingStairsConstraintDP}
/* 带约束爬楼梯:动态规划 */
function climbingStairsConstraintDP(n: number): number {
if (n === 1 || n === 2) {
return 1;
}
// 初始化 dp 表,用于存储子问题的解
const dp = Array.from({ length: n + 1 }, () => new Array(3));
// 初始状态:预设最小子问题的解
dp[1][1] = 1;
dp[1][2] = 0;
dp[2][1] = 0;
dp[2][2] = 1;
// 状态转移:从较小子问题逐步求解较大子问题
for (let i = 3; i <= n; i++) {
dp[i][1] = dp[i - 1][2];
dp[i][2] = dp[i - 2][1] + dp[i - 2][2];
}
return dp[n][1] + dp[n][2];
}
```
=== "Dart"
```dart title="climbing_stairs_constraint_dp.dart"
[class]{}-[func]{climbingStairsConstraintDP}
/* 带约束爬楼梯:动态规划 */
int climbingStairsConstraintDP(int n) {
if (n == 1 || n == 2) {
return 1;
}
// 初始化 dp 表,用于存储子问题的解
List<List<int>> dp = List.generate(n + 1, (index) => List.filled(3, 0));
// 初始状态:预设最小子问题的解
dp[1][1] = 1;
dp[1][2] = 0;
dp[2][1] = 0;
dp[2][2] = 1;
// 状态转移:从较小子问题逐步求解较大子问题
for (int i = 3; i <= n; i++) {
dp[i][1] = dp[i - 1][2];
dp[i][2] = dp[i - 2][1] + dp[i - 2][2];
}
return dp[n][1] + dp[n][2];
}
```
=== "Rust"
```rust title="climbing_stairs_constraint_dp.rs"
[class]{}-[func]{climbing_stairs_constraint_dp}
/* 带约束爬楼梯:动态规划 */
fn climbing_stairs_constraint_dp(n: usize) -> i32 {
if n == 1 || n == 2 { return 1 };
// 初始化 dp 表,用于存储子问题的解
let mut dp = vec![vec![-1; 3]; n + 1];
// 初始状态:预设最小子问题的解
dp[1][1] = 1;
dp[1][2] = 0;
dp[2][1] = 0;
dp[2][2] = 1;
// 状态转移:从较小子问题逐步求解较大子问题
for i in 3..=n {
dp[i][1] = dp[i - 1][2];
dp[i][2] = dp[i - 2][1] + dp[i - 2][2];
}
dp[n][1] + dp[n][2]
}
```
=== "C"
@@ -303,7 +776,25 @@ $$
=== "Zig"
```zig title="climbing_stairs_constraint_dp.zig"
[class]{}-[func]{climbingStairsConstraintDP}
// 带约束爬楼梯:动态规划
fn climbingStairsConstraintDP(comptime n: usize) i32 {
if (n == 1 or n == 2) {
return 1;
}
// 初始化 dp 表,用于存储子问题的解
var dp = [_][3]i32{ [_]i32{ -1, -1, -1 } } ** (n + 1);
// 初始状态:预设最小子问题的解
dp[1][1] = 1;
dp[1][2] = 0;
dp[2][1] = 0;
dp[2][2] = 1;
// 状态转移:从较小子问题逐步求解较大子问题
for (3..n + 1) |i| {
dp[i][1] = dp[i - 1][2];
dp[i][2] = dp[i - 2][1] + dp[i - 2][2];
}
return dp[n][1] + dp[n][2];
}
```
在上面的案例中,由于仅需多考虑前面一个状态,我们仍然可以通过扩展状态定义,使得问题重新满足无后效性。然而,某些问题具有非常严重的“有后效性”。

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@@ -80,61 +80,312 @@ $$
=== "Python"
```python title="edit_distance.py"
[class]{}-[func]{edit_distance_dp}
def edit_distance_dp(s: str, t: str) -> int:
"""编辑距离:动态规划"""
n, m = len(s), len(t)
dp = [[0] * (m + 1) for _ in range(n + 1)]
# 状态转移:首行首列
for i in range(1, n + 1):
dp[i][0] = i
for j in range(1, m + 1):
dp[0][j] = j
# 状态转移:其余行列
for i in range(1, n + 1):
for j in range(1, m + 1):
if s[i - 1] == t[j - 1]:
# 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1]
else:
# 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] = min(dp[i][j - 1], dp[i - 1][j], dp[i - 1][j - 1]) + 1
return dp[n][m]
```
=== "C++"
```cpp title="edit_distance.cpp"
[class]{}-[func]{editDistanceDP}
/* 编辑距离:动态规划 */
int editDistanceDP(string s, string t) {
int n = s.length(), m = t.length();
vector<vector<int>> dp(n + 1, vector<int>(m + 1, 0));
// 状态转移:首行首列
for (int i = 1; i <= n; i++) {
dp[i][0] = i;
}
for (int j = 1; j <= m; j++) {
dp[0][j] = j;
}
// 状态转移:其余行列
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (s[i - 1] == t[j - 1]) {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1];
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] = min(min(dp[i][j - 1], dp[i - 1][j]), dp[i - 1][j - 1]) + 1;
}
}
}
return dp[n][m];
}
```
=== "Java"
```java title="edit_distance.java"
[class]{edit_distance}-[func]{editDistanceDP}
/* 编辑距离:动态规划 */
int editDistanceDP(String s, String t) {
int n = s.length(), m = t.length();
int[][] dp = new int[n + 1][m + 1];
// 状态转移:首行首列
for (int i = 1; i <= n; i++) {
dp[i][0] = i;
}
for (int j = 1; j <= m; j++) {
dp[0][j] = j;
}
// 状态转移:其余行列
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (s.charAt(i - 1) == t.charAt(j - 1)) {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1];
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] = Math.min(Math.min(dp[i][j - 1], dp[i - 1][j]), dp[i - 1][j - 1]) + 1;
}
}
}
return dp[n][m];
}
```
=== "C#"
```csharp title="edit_distance.cs"
[class]{edit_distance}-[func]{editDistanceDP}
/* 编辑距离:动态规划 */
int editDistanceDP(string s, string t) {
int n = s.Length, m = t.Length;
int[,] dp = new int[n + 1, m + 1];
// 状态转移:首行首列
for (int i = 1; i <= n; i++) {
dp[i, 0] = i;
}
for (int j = 1; j <= m; j++) {
dp[0, j] = j;
}
// 状态转移:其余行列
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (s[i - 1] == t[j - 1]) {
// 若两字符相等,则直接跳过此两字符
dp[i, j] = dp[i - 1, j - 1];
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i, j] = Math.Min(Math.Min(dp[i, j - 1], dp[i - 1, j]), dp[i - 1, j - 1]) + 1;
}
}
}
return dp[n, m];
}
```
=== "Go"
```go title="edit_distance.go"
[class]{}-[func]{editDistanceDP}
/* 编辑距离:动态规划 */
func editDistanceDP(s string, t string) int {
n := len(s)
m := len(t)
dp := make([][]int, n+1)
for i := 0; i <= n; i++ {
dp[i] = make([]int, m+1)
}
// 状态转移:首行首列
for i := 1; i <= n; i++ {
dp[i][0] = i
}
for j := 1; j <= m; j++ {
dp[0][j] = j
}
// 状态转移:其余行列
for i := 1; i <= n; i++ {
for j := 1; j <= m; j++ {
if s[i-1] == t[j-1] {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i-1][j-1]
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] = MinInt(MinInt(dp[i][j-1], dp[i-1][j]), dp[i-1][j-1]) + 1
}
}
}
return dp[n][m]
}
```
=== "Swift"
```swift title="edit_distance.swift"
[class]{}-[func]{editDistanceDP}
/* 编辑距离:动态规划 */
func editDistanceDP(s: String, t: String) -> Int {
let n = s.utf8CString.count
let m = t.utf8CString.count
var dp = Array(repeating: Array(repeating: 0, count: m + 1), count: n + 1)
// 状态转移:首行首列
for i in stride(from: 1, through: n, by: 1) {
dp[i][0] = i
}
for j in stride(from: 1, through: m, by: 1) {
dp[0][j] = j
}
// 状态转移:其余行列
for i in stride(from: 1, through: n, by: 1) {
for j in stride(from: 1, through: m, by: 1) {
if s.utf8CString[i - 1] == t.utf8CString[j - 1] {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1]
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] = min(min(dp[i][j - 1], dp[i - 1][j]), dp[i - 1][j - 1]) + 1
}
}
}
return dp[n][m]
}
```
=== "JS"
```javascript title="edit_distance.js"
[class]{}-[func]{editDistanceDP}
/* 编辑距离:动态规划 */
function editDistanceDP(s, t) {
const n = s.length,
m = t.length;
const dp = Array.from({ length: n + 1 }, () => new Array(m + 1).fill(0));
// 状态转移:首行首列
for (let i = 1; i <= n; i++) {
dp[i][0] = i;
}
for (let j = 1; j <= m; j++) {
dp[0][j] = j;
}
// 状态转移:其余行列
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= m; j++) {
if (s.charAt(i - 1) === t.charAt(j - 1)) {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1];
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] =
Math.min(
Math.min(dp[i][j - 1], dp[i - 1][j]),
dp[i - 1][j - 1]
) + 1;
}
}
}
return dp[n][m];
}
```
=== "TS"
```typescript title="edit_distance.ts"
[class]{}-[func]{editDistanceDP}
/* 编辑距离:动态规划 */
function editDistanceDP(s: string, t: string): number {
const n = s.length,
m = t.length;
const dp = Array.from({ length: n + 1 }, () =>
Array.from({ length: m + 1 }, () => 0)
);
// 状态转移:首行首列
for (let i = 1; i <= n; i++) {
dp[i][0] = i;
}
for (let j = 1; j <= m; j++) {
dp[0][j] = j;
}
// 状态转移:其余行列
for (let i = 1; i <= n; i++) {
for (let j = 1; j <= m; j++) {
if (s.charAt(i - 1) === t.charAt(j - 1)) {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1];
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] =
Math.min(
Math.min(dp[i][j - 1], dp[i - 1][j]),
dp[i - 1][j - 1]
) + 1;
}
}
}
return dp[n][m];
}
```
=== "Dart"
```dart title="edit_distance.dart"
[class]{}-[func]{editDistanceDP}
/* 编辑距离:动态规划 */
int editDistanceDP(String s, String t) {
int n = s.length, m = t.length;
List<List<int>> dp = List.generate(n + 1, (_) => List.filled(m + 1, 0));
// 状态转移:首行首列
for (int i = 1; i <= n; i++) {
dp[i][0] = i;
}
for (int j = 1; j <= m; j++) {
dp[0][j] = j;
}
// 状态转移:其余行列
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (s[i - 1] == t[j - 1]) {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1];
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] = min(min(dp[i][j - 1], dp[i - 1][j]), dp[i - 1][j - 1]) + 1;
}
}
}
return dp[n][m];
}
```
=== "Rust"
```rust title="edit_distance.rs"
[class]{}-[func]{edit_distance_dp}
/* 编辑距离:动态规划 */
fn edit_distance_dp(s: &str, t: &str) -> i32 {
let (n, m) = (s.len(), t.len());
let mut dp = vec![vec![0; m + 1]; n + 1];
// 状态转移:首行首列
for i in 1..= n {
dp[i][0] = i as i32;
}
for j in 1..m {
dp[0][j] = j as i32;
}
// 状态转移:其余行列
for i in 1..=n {
for j in 1..=m {
if s.chars().nth(i - 1) == t.chars().nth(j - 1) {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1];
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] = std::cmp::min(std::cmp::min(dp[i][j - 1], dp[i - 1][j]), dp[i - 1][j - 1]) + 1;
}
}
}
dp[n][m]
}
```
=== "C"
@@ -146,7 +397,32 @@ $$
=== "Zig"
```zig title="edit_distance.zig"
[class]{}-[func]{editDistanceDP}
// 编辑距离:动态规划
fn editDistanceDP(comptime s: []const u8, comptime t: []const u8) i32 {
comptime var n = s.len;
comptime var m = t.len;
var dp = [_][m + 1]i32{[_]i32{0} ** (m + 1)} ** (n + 1);
// 状态转移:首行首列
for (1..n + 1) |i| {
dp[i][0] = @intCast(i);
}
for (1..m + 1) |j| {
dp[0][j] = @intCast(j);
}
// 状态转移:其余行列
for (1..n + 1) |i| {
for (1..m + 1) |j| {
if (s[i - 1] == t[j - 1]) {
// 若两字符相等,则直接跳过此两字符
dp[i][j] = dp[i - 1][j - 1];
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[i][j] = @min(@min(dp[i][j - 1], dp[i - 1][j]), dp[i - 1][j - 1]) + 1;
}
}
}
return dp[n][m];
}
```
如图 14-30 所示,编辑距离问题的状态转移过程与背包问题非常类似,都可以看作是填写一个二维网格的过程。
@@ -207,61 +483,330 @@ $$
=== "Python"
```python title="edit_distance.py"
[class]{}-[func]{edit_distance_dp_comp}
def edit_distance_dp_comp(s: str, t: str) -> int:
"""编辑距离:空间优化后的动态规划"""
n, m = len(s), len(t)
dp = [0] * (m + 1)
# 状态转移:首行
for j in range(1, m + 1):
dp[j] = j
# 状态转移:其余行
for i in range(1, n + 1):
# 状态转移:首列
leftup = dp[0] # 暂存 dp[i-1, j-1]
dp[0] += 1
# 状态转移:其余列
for j in range(1, m + 1):
temp = dp[j]
if s[i - 1] == t[j - 1]:
# 若两字符相等,则直接跳过此两字符
dp[j] = leftup
else:
# 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = min(dp[j - 1], dp[j], leftup) + 1
leftup = temp # 更新为下一轮的 dp[i-1, j-1]
return dp[m]
```
=== "C++"
```cpp title="edit_distance.cpp"
[class]{}-[func]{editDistanceDPComp}
/* 编辑距离:空间优化后的动态规划 */
int editDistanceDPComp(string s, string t) {
int n = s.length(), m = t.length();
vector<int> dp(m + 1, 0);
// 状态转移:首行
for (int j = 1; j <= m; j++) {
dp[j] = j;
}
// 状态转移:其余行
for (int i = 1; i <= n; i++) {
// 状态转移:首列
int leftup = dp[0]; // 暂存 dp[i-1, j-1]
dp[0] = i;
// 状态转移:其余列
for (int j = 1; j <= m; j++) {
int temp = dp[j];
if (s[i - 1] == t[j - 1]) {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup;
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = min(min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m];
}
```
=== "Java"
```java title="edit_distance.java"
[class]{edit_distance}-[func]{editDistanceDPComp}
/* 编辑距离:空间优化后的动态规划 */
int editDistanceDPComp(String s, String t) {
int n = s.length(), m = t.length();
int[] dp = new int[m + 1];
// 状态转移:首行
for (int j = 1; j <= m; j++) {
dp[j] = j;
}
// 状态转移:其余行
for (int i = 1; i <= n; i++) {
// 状态转移:首列
int leftup = dp[0]; // 暂存 dp[i-1, j-1]
dp[0] = i;
// 状态转移:其余列
for (int j = 1; j <= m; j++) {
int temp = dp[j];
if (s.charAt(i - 1) == t.charAt(j - 1)) {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup;
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = Math.min(Math.min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m];
}
```
=== "C#"
```csharp title="edit_distance.cs"
[class]{edit_distance}-[func]{editDistanceDPComp}
/* 编辑距离:空间优化后的动态规划 */
int editDistanceDPComp(string s, string t) {
int n = s.Length, m = t.Length;
int[] dp = new int[m + 1];
// 状态转移:首行
for (int j = 1; j <= m; j++) {
dp[j] = j;
}
// 状态转移:其余行
for (int i = 1; i <= n; i++) {
// 状态转移:首列
int leftup = dp[0]; // 暂存 dp[i-1, j-1]
dp[0] = i;
// 状态转移:其余列
for (int j = 1; j <= m; j++) {
int temp = dp[j];
if (s[i - 1] == t[j - 1]) {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup;
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = Math.Min(Math.Min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m];
}
```
=== "Go"
```go title="edit_distance.go"
[class]{}-[func]{editDistanceDPComp}
/* 编辑距离:空间优化后的动态规划 */
func editDistanceDPComp(s string, t string) int {
n := len(s)
m := len(t)
dp := make([]int, m+1)
// 状态转移:首行
for j := 1; j <= m; j++ {
dp[j] = j
}
// 状态转移:其余行
for i := 1; i <= n; i++ {
// 状态转移:首列
leftUp := dp[0] // 暂存 dp[i-1, j-1]
dp[0] = i
// 状态转移:其余列
for j := 1; j <= m; j++ {
temp := dp[j]
if s[i-1] == t[j-1] {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftUp
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = MinInt(MinInt(dp[j-1], dp[j]), leftUp) + 1
}
leftUp = temp // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m]
}
```
=== "Swift"
```swift title="edit_distance.swift"
[class]{}-[func]{editDistanceDPComp}
/* 编辑距离:空间优化后的动态规划 */
func editDistanceDPComp(s: String, t: String) -> Int {
let n = s.utf8CString.count
let m = t.utf8CString.count
var dp = Array(repeating: 0, count: m + 1)
// 状态转移:首行
for j in stride(from: 1, through: m, by: 1) {
dp[j] = j
}
// 状态转移:其余行
for i in stride(from: 1, through: n, by: 1) {
// 状态转移:首列
var leftup = dp[0] // 暂存 dp[i-1, j-1]
dp[0] = i
// 状态转移:其余列
for j in stride(from: 1, through: m, by: 1) {
let temp = dp[j]
if s.utf8CString[i - 1] == t.utf8CString[j - 1] {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = min(min(dp[j - 1], dp[j]), leftup) + 1
}
leftup = temp // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m]
}
```
=== "JS"
```javascript title="edit_distance.js"
[class]{}-[func]{editDistanceDPComp}
/* 编辑距离:状态压缩后的动态规划 */
function editDistanceDPComp(s, t) {
const n = s.length,
m = t.length;
const dp = new Array(m + 1).fill(0);
// 状态转移:首行
for (let j = 1; j <= m; j++) {
dp[j] = j;
}
// 状态转移:其余行
for (let i = 1; i <= n; i++) {
// 状态转移:首列
let leftup = dp[0]; // 暂存 dp[i-1, j-1]
dp[0] = i;
// 状态转移:其余列
for (let j = 1; j <= m; j++) {
const temp = dp[j];
if (s.charAt(i - 1) === t.charAt(j - 1)) {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup;
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = Math.min(Math.min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m];
}
```
=== "TS"
```typescript title="edit_distance.ts"
[class]{}-[func]{editDistanceDPComp}
/* 编辑距离:状态压缩后的动态规划 */
function editDistanceDPComp(s: string, t: string): number {
const n = s.length,
m = t.length;
const dp = new Array(m + 1).fill(0);
// 状态转移:首行
for (let j = 1; j <= m; j++) {
dp[j] = j;
}
// 状态转移:其余行
for (let i = 1; i <= n; i++) {
// 状态转移:首列
let leftup = dp[0]; // 暂存 dp[i-1, j-1]
dp[0] = i;
// 状态转移:其余列
for (let j = 1; j <= m; j++) {
const temp = dp[j];
if (s.charAt(i - 1) === t.charAt(j - 1)) {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup;
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = Math.min(Math.min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m];
}
```
=== "Dart"
```dart title="edit_distance.dart"
[class]{}-[func]{editDistanceDPComp}
/* 编辑距离:空间优化后的动态规划 */
int editDistanceDPComp(String s, String t) {
int n = s.length, m = t.length;
List<int> dp = List.filled(m + 1, 0);
// 状态转移:首行
for (int j = 1; j <= m; j++) {
dp[j] = j;
}
// 状态转移:其余行
for (int i = 1; i <= n; i++) {
// 状态转移:首列
int leftup = dp[0]; // 暂存 dp[i-1, j-1]
dp[0] = i;
// 状态转移:其余列
for (int j = 1; j <= m; j++) {
int temp = dp[j];
if (s[i - 1] == t[j - 1]) {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup;
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = min(min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m];
}
```
=== "Rust"
```rust title="edit_distance.rs"
[class]{}-[func]{edit_distance_dp_comp}
/* 编辑距离:空间优化后的动态规划 */
fn edit_distance_dp_comp(s: &str, t: &str) -> i32 {
let (n, m) = (s.len(), t.len());
let mut dp = vec![0; m + 1];
// 状态转移:首行
for j in 1..m {
dp[j] = j as i32;
}
// 状态转移:其余行
for i in 1..=n {
// 状态转移:首列
let mut leftup = dp[0]; // 暂存 dp[i-1, j-1]
dp[0] = i as i32;
// 状态转移:其余列
for j in 1..=m {
let temp = dp[j];
if s.chars().nth(i - 1) == t.chars().nth(j - 1) {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup;
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = std::cmp::min(std::cmp::min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // 更新为下一轮的 dp[i-1, j-1]
}
}
dp[m]
}
```
=== "C"
@@ -273,5 +818,33 @@ $$
=== "Zig"
```zig title="edit_distance.zig"
[class]{}-[func]{editDistanceDPComp}
// 编辑距离:空间优化后的动态规划
fn editDistanceDPComp(comptime s: []const u8, comptime t: []const u8) i32 {
comptime var n = s.len;
comptime var m = t.len;
var dp = [_]i32{0} ** (m + 1);
// 状态转移:首行
for (1..m + 1) |j| {
dp[j] = @intCast(j);
}
// 状态转移:其余行
for (1..n + 1) |i| {
// 状态转移:首列
var leftup = dp[0]; // 暂存 dp[i-1, j-1]
dp[0] = @intCast(i);
// 状态转移:其余列
for (1..m + 1) |j| {
var temp = dp[j];
if (s[i - 1] == t[j - 1]) {
// 若两字符相等,则直接跳过此两字符
dp[j] = leftup;
} else {
// 最少编辑步数 = 插入、删除、替换这三种操作的最少编辑步数 + 1
dp[j] = @min(@min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // 更新为下一轮的 dp[i-1, j-1]
}
}
return dp[m];
}
```

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