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Retranslate the complete English edition from Simplified Chinese (#2010)

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* Retranslate the complete English edition from Simplified Chinese

* Polish three English explanations after reader-focused review
This commit is contained in:
Yudong Jin
2026-10-31 03:35:51 +08:00
committed by GitHub
parent ef46e2ed95
commit 14c314c08c
1502 changed files with 29459 additions and 23517 deletions
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66
en/codes/java/chapter_dynamic_programming/edit_distance.java
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@@ -9,73 +9,73 @@ package chapter_dynamic_programming;
import java.util.Arrays;
public class edit_distance {
/* Edit distance: Brute-force search */
/* Edit distance: brute-force search */
static int editDistanceDFS(String s, String t, int i, int j) {
// If both s and t are empty, return 0
// If the current prefixes of s and t are both empty, return 0
if (i == 0 && j == 0)
return 0;
// If s is empty, return length of t
// If the current prefix of s is empty, return j, the length of the current prefix of t
if (i == 0)
return j;
// If t is empty, return length of s
// If the current prefix of t is empty, return i, the length of the current prefix of s
if (j == 0)
return i;
// If two characters are equal, skip both characters
// If the two characters are equal, skip both of them
if (s.charAt(i - 1) == t.charAt(j - 1))
return editDistanceDFS(s, t, i - 1, j - 1);
// Minimum edit steps = minimum edit steps of insert, delete, replace + 1
// Minimum edits = the minimum among the insertion, deletion, and replacement subproblems + 1
int insert = editDistanceDFS(s, t, i, j - 1);
int delete = editDistanceDFS(s, t, i - 1, j);
int replace = editDistanceDFS(s, t, i - 1, j - 1);
// Return minimum edit steps
// Return the minimum number of edits
return Math.min(Math.min(insert, delete), replace) + 1;
}
/* Edit distance: Memoization search */
/* Edit distance: memoized search */
static int editDistanceDFSMem(String s, String t, int[][] mem, int i, int j) {
// If both s and t are empty, return 0
// If the current prefixes of s and t are both empty, return 0
if (i == 0 && j == 0)
return 0;
// If s is empty, return length of t
// If the current prefix of s is empty, return j, the length of the current prefix of t
if (i == 0)
return j;
// If t is empty, return length of s
// If the current prefix of t is empty, return i, the length of the current prefix of s
if (j == 0)
return i;
// If there's a record, return it directly
// If a result has already been recorded, return it directly
if (mem[i][j] != -1)
return mem[i][j];
// If two characters are equal, skip both characters
// If the two characters are equal, skip both of them
if (s.charAt(i - 1) == t.charAt(j - 1))
return editDistanceDFSMem(s, t, mem, i - 1, j - 1);
// Minimum edit steps = minimum edit steps of insert, delete, replace + 1
// Minimum edits = the minimum among the insertion, deletion, and replacement subproblems + 1
int insert = editDistanceDFSMem(s, t, mem, i, j - 1);
int delete = editDistanceDFSMem(s, t, mem, i - 1, j);
int replace = editDistanceDFSMem(s, t, mem, i - 1, j - 1);
// Record and return minimum edit steps
// Record and return the minimum number of edits
mem[i][j] = Math.min(Math.min(insert, delete), replace) + 1;
return mem[i][j];
}
/* Edit distance: Dynamic programming */
/* Edit distance: dynamic programming */
static int editDistanceDP(String s, String t) {
int n = s.length(), m = t.length();
int[][] dp = new int[n + 1][m + 1];
// State transition: first row and first column
// State transitions: first row and first column
for (int i = 1; i <= n; i++) {
dp[i][0] = i;
}
for (int j = 1; j <= m; j++) {
dp[0][j] = j;
}
// State transition: rest of the rows and columns
// State transitions: remaining rows and columns
for (int i = 1; i <= n; i++) {
for (int j = 1; j <= m; j++) {
if (s.charAt(i - 1) == t.charAt(j - 1)) {
// If two characters are equal, skip both characters
// If the two characters are equal, skip both of them
dp[i][j] = dp[i - 1][j - 1];
} else {
// Minimum edit steps = minimum edit steps of insert, delete, replace + 1
// Minimum edits = the minimum among the insertion, deletion, and replacement subproblems + 1
dp[i][j] = Math.min(Math.min(dp[i][j - 1], dp[i - 1][j]), dp[i - 1][j - 1]) + 1;
}
}
@@ -83,30 +83,30 @@ public class edit_distance {
return dp[n][m];
}
/* Edit distance: Space-optimized dynamic programming */
/* Edit distance: space-optimized dynamic programming */
static int editDistanceDPComp(String s, String t) {
int n = s.length(), m = t.length();
int[] dp = new int[m + 1];
// State transition: first row
// State transitions: first row
for (int j = 1; j <= m; j++) {
dp[j] = j;
}
// State transition: rest of the rows
// State transitions: remaining rows
for (int i = 1; i <= n; i++) {
// State transition: first column
// State transitions: first column
int leftup = dp[0]; // Temporarily store dp[i-1, j-1]
dp[0] = i;
// State transition: rest of the columns
// State transitions: remaining columns
for (int j = 1; j <= m; j++) {
int temp = dp[j];
if (s.charAt(i - 1) == t.charAt(j - 1)) {
// If two characters are equal, skip both characters
// If the two characters are equal, skip both of them
dp[j] = leftup;
} else {
// Minimum edit steps = minimum edit steps of insert, delete, replace + 1
// Minimum edits = the minimum among the insertion, deletion, and replacement subproblems + 1
dp[j] = Math.min(Math.min(dp[j - 1], dp[j]), leftup) + 1;
}
leftup = temp; // Update for next round's dp[i-1, j-1]
leftup = temp; // Update to dp[i-1, j-1] for the next iteration
}
}
return dp[m];
@@ -119,21 +119,21 @@ public class edit_distance {
// Brute-force search
int res = editDistanceDFS(s, t, n, m);
System.out.println("Changing " + s + " to " + t + " requires a minimum of " + res + " edits");
System.out.println("Changing " + s + " to " + t + " requires at least " + res + " edits");
// Memoization search
// Memoized search
int[][] mem = new int[n + 1][m + 1];
for (int[] row : mem)
Arrays.fill(row, -1);
res = editDistanceDFSMem(s, t, mem, n, m);
System.out.println("Changing " + s + " to " + t + " requires a minimum of " + res + " edits");
System.out.println("Changing " + s + " to " + t + " requires at least " + res + " edits");
// Dynamic programming
res = editDistanceDP(s, t);
System.out.println("Changing " + s + " to " + t + " requires a minimum of " + res + " edits");
System.out.println("Changing " + s + " to " + t + " requires at least " + res + " edits");
// Space-optimized dynamic programming
res = editDistanceDPComp(s, t);
System.out.println("Changing " + s + " to " + t + " requires a minimum of " + res + " edits");
System.out.println("Changing " + s + " to " + t + " requires at least " + res + " edits");
}
}