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krahets
2023-10-08 01:43:28 +08:00
parent 3d2d669b43
commit baac2d11a7
52 changed files with 999 additions and 625 deletions
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zh/chapter_backtracking/backtracking_algorithm.md
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@@ -66,7 +66,7 @@ comments: true
```csharp title="preorder_traversal_i_compact.cs"
/* 前序遍历：例题一 */
void preOrder(TreeNode root) {
void PreOrder(TreeNode root) {
if (root == null) {
return;
}
@@ -74,8 +74,8 @@ comments: true
// 记录解
res.Add(root);
}
preOrder(root.left);
preOrder(root.right);
PreOrder(root.left);
PreOrder(root.right);
}
```
@@ -277,7 +277,7 @@ comments: true
```csharp title="preorder_traversal_ii_compact.cs"
/* 前序遍历：例题二 */
void preOrder(TreeNode root) {
void PreOrder(TreeNode root) {
if (root == null) {
return;
}
@@ -287,8 +287,8 @@ comments: true
// 记录解
res.Add(new List<TreeNode>(path));
}
preOrder(root.left);
preOrder(root.right);
PreOrder(root.left);
PreOrder(root.right);
// 回退
path.RemoveAt(path.Count - 1);
}
@@ -580,7 +580,7 @@ comments: true
```csharp title="preorder_traversal_iii_compact.cs"
/* 前序遍历：例题三 */
void preOrder(TreeNode root) {
void PreOrder(TreeNode root) {
// 剪枝
if (root == null || root.val == 3) {
return;
@@ -591,8 +591,8 @@ comments: true
// 记录解
res.Add(new List<TreeNode>(path));
}
preOrder(root.left);
preOrder(root.right);
PreOrder(root.left);
PreOrder(root.right);
// 回退
path.RemoveAt(path.Count - 1);
}
@@ -865,23 +865,23 @@ comments: true
```csharp title=""
/* 回溯算法框架 */
void backtrack(State state, List<Choice> choices, List<State> res) {
void Backtrack(State state, List<Choice> choices, List<State> res) {
// 判断是否为解
if (isSolution(state)) {
if (IsSolution(state)) {
// 记录解
recordSolution(state, res);
RecordSolution(state, res);
// 停止继续搜索
return;
}
// 遍历所有选择
foreach (Choice choice in choices) {
// 剪枝：判断选择是否合法
if (isValid(state, choice)) {
if (IsValid(state, choice)) {
// 尝试：做出选择，更新状态
makeChoice(state, choice);
backtrack(state, choices, res);
MakeChoice(state, choice);
Backtrack(state, choices, res);
// 回退：撤销选择，恢复到之前的状态
undoChoice(state, choice);
UndoChoice(state, choice);
}
}
}
@@ -1225,47 +1225,47 @@ comments: true
```csharp title="preorder_traversal_iii_template.cs"
/* 判断当前状态是否为解 */
bool isSolution(List<TreeNode> state) {
bool IsSolution(List<TreeNode> state) {
return state.Count != 0 && state[^1].val == 7;
}
/* 记录解 */
void recordSolution(List<TreeNode> state, List<List<TreeNode>> res) {
void RecordSolution(List<TreeNode> state, List<List<TreeNode>> res) {
res.Add(new List<TreeNode>(state));
}
/* 判断在当前状态下，该选择是否合法 */
bool isValid(List<TreeNode> state, TreeNode choice) {
bool IsValid(List<TreeNode> state, TreeNode choice) {
return choice != null && choice.val != 3;
}
/* 更新状态 */
void makeChoice(List<TreeNode> state, TreeNode choice) {
void MakeChoice(List<TreeNode> state, TreeNode choice) {
state.Add(choice);
}
/* 恢复状态 */
void undoChoice(List<TreeNode> state, TreeNode choice) {
void UndoChoice(List<TreeNode> state, TreeNode choice) {
state.RemoveAt(state.Count - 1);
}
/* 回溯算法：例题三 */
void backtrack(List<TreeNode> state, List<TreeNode> choices, List<List<TreeNode>> res) {
void Backtrack(List<TreeNode> state, List<TreeNode> choices, List<List<TreeNode>> res) {
// 检查是否为解
if (isSolution(state)) {
if (IsSolution(state)) {
// 记录解
recordSolution(state, res);
RecordSolution(state, res);
}
// 遍历所有选择
foreach (TreeNode choice in choices) {
// 剪枝：检查选择是否合法
if (isValid(state, choice)) {
if (IsValid(state, choice)) {
// 尝试：做出选择，更新状态
makeChoice(state, choice);
MakeChoice(state, choice);
// 进行下一轮选择
backtrack(state, new List<TreeNode> { choice.left, choice.right }, res);
Backtrack(state, new List<TreeNode> { choice.left, choice.right }, res);
// 回退：撤销选择，恢复到之前的状态
undoChoice(state, choice);
UndoChoice(state, choice);
}
}
}