mirror of
https://github.com/halfrost/LeetCode-Go.git
synced 2025-07-24 02:14:00 +08:00
146 lines
7.5 KiB
Markdown
146 lines
7.5 KiB
Markdown
---
|
|
title: 2.08 ✅ Backtracking
|
|
type: docs
|
|
weight: 8
|
|
---
|
|
|
|
# Backtracking
|
|
|
|
|
|
|
|
- 排列问题 Permutations。第 46 题，第 47 题。第 60 题，第 526 题，第 996 题。
|
|
- 组合问题 Combination。第 39 题，第 40 题，第 77 题，第 216 题。
|
|
- 排列和组合杂交问题。第 1079 题。
|
|
- N 皇后终极解法(二进制解法)。第 51 题，第 52 题。
|
|
- 数独问题。第 37 题。
|
|
- 四个方向搜索。第 79 题，第 212 题，第 980 题。
|
|
- 子集合问题。第 78 题，第 90 题。
|
|
- Trie。第 208 题，第 211 题。
|
|
- BFS 优化。第 126 题，第 127 题。
|
|
- DFS 模板。(只是一个例子，不对应任何题)
|
|
|
|
```go
|
|
func combinationSum2(candidates []int, target int) [][]int {
|
|
if len(candidates) == 0 {
|
|
return [][]int{}
|
|
}
|
|
c, res := []int{}, [][]int{}
|
|
sort.Ints(candidates)
|
|
findcombinationSum2(candidates, target, 0, c, &res)
|
|
return res
|
|
}
|
|
|
|
func findcombinationSum2(nums []int, target, index int, c []int, res *[][]int) {
|
|
if target == 0 {
|
|
b := make([]int, len(c))
|
|
copy(b, c)
|
|
*res = append(*res, b)
|
|
return
|
|
}
|
|
for i := index; i < len(nums); i++ {
|
|
if i > index && nums[i] == nums[i-1] { // 这里是去重的关键逻辑
|
|
continue
|
|
}
|
|
if target >= nums[i] {
|
|
c = append(c, nums[i])
|
|
findcombinationSum2(nums, target-nums[i], i+1, c, res)
|
|
c = c[:len(c)-1]
|
|
}
|
|
}
|
|
}
|
|
```
|
|
- BFS 模板。(只是一个例子，不对应任何题)
|
|
|
|
```go
|
|
func updateMatrix_BFS(matrix [][]int) [][]int {
|
|
res := make([][]int, len(matrix))
|
|
if len(matrix) == 0 || len(matrix[0]) == 0 {
|
|
return res
|
|
}
|
|
queue := make([][]int, 0)
|
|
for i, _ := range matrix {
|
|
res[i] = make([]int, len(matrix[0]))
|
|
for j, _ := range res[i] {
|
|
if matrix[i][j] == 0 {
|
|
res[i][j] = -1
|
|
queue = append(queue, []int{i, j})
|
|
}
|
|
}
|
|
}
|
|
level := 1
|
|
for len(queue) > 0 {
|
|
size := len(queue)
|
|
for size > 0 {
|
|
size -= 1
|
|
node := queue[0]
|
|
queue = queue[1:]
|
|
i, j := node[0], node[1]
|
|
for _, direction := range [][]int{{-1, 0}, {1, 0}, {0, 1}, {0, -1}} {
|
|
x := i + direction[0]
|
|
y := j + direction[1]
|
|
if x < 0 || x >= len(matrix) || y < 0 || y >= len(matrix[0]) || res[x][y] < 0 || res[x][y] > 0 {
|
|
continue
|
|
}
|
|
res[x][y] = level
|
|
queue = append(queue, []int{x, y})
|
|
}
|
|
}
|
|
level++
|
|
}
|
|
for i, row := range res {
|
|
for j, cell := range row {
|
|
if cell == -1 {
|
|
res[i][j] = 0
|
|
}
|
|
}
|
|
}
|
|
return res
|
|
}
|
|
```
|
|
|
|
| No. | Title | Solution | Difficulty | TimeComplexity | SpaceComplexity |Favorite| Acceptance |
|
|
|:--------:|:------- | :--------: | :----------: | :----: | :-----: | :-----: |:-----: |
|
|
|0017|Letter Combinations of a Phone Number|[Go]({{< relref "/ChapterFour/0001~0099/0017.Letter-Combinations-of-a-Phone-Number.md" >}})|Medium| O(log n)| O(1)||50.3%|
|
|
|0022|Generate Parentheses|[Go]({{< relref "/ChapterFour/0001~0099/0022.Generate-Parentheses.md" >}})|Medium| O(log n)| O(1)||66.1%|
|
|
|0037|Sudoku Solver|[Go]({{< relref "/ChapterFour/0001~0099/0037.Sudoku-Solver.md" >}})|Hard| O(n^2)| O(n^2)|❤️|47.7%|
|
|
|0039|Combination Sum|[Go]({{< relref "/ChapterFour/0001~0099/0039.Combination-Sum.md" >}})|Medium| O(n log n)| O(n)||60.2%|
|
|
|0040|Combination Sum II|[Go]({{< relref "/ChapterFour/0001~0099/0040.Combination-Sum-II.md" >}})|Medium| O(n log n)| O(n)||50.7%|
|
|
|0046|Permutations|[Go]({{< relref "/ChapterFour/0001~0099/0046.Permutations.md" >}})|Medium| O(n)| O(n)|❤️|67.6%|
|
|
|0047|Permutations II|[Go]({{< relref "/ChapterFour/0001~0099/0047.Permutations-II.md" >}})|Medium| O(n^2)| O(n)|❤️|50.2%|
|
|
|0051|N-Queens|[Go]({{< relref "/ChapterFour/0001~0099/0051.N-Queens.md" >}})|Hard| O(n!)| O(n)|❤️|51.1%|
|
|
|0052|N-Queens II|[Go]({{< relref "/ChapterFour/0001~0099/0052.N-Queens-II.md" >}})|Hard| O(n!)| O(n)|❤️|61.1%|
|
|
|0060|Permutation Sequence|[Go]({{< relref "/ChapterFour/0001~0099/0060.Permutation-Sequence.md" >}})|Hard| O(n log n)| O(1)||39.8%|
|
|
|0077|Combinations|[Go]({{< relref "/ChapterFour/0001~0099/0077.Combinations.md" >}})|Medium| O(n)| O(n)|❤️|58.5%|
|
|
|0078|Subsets|[Go]({{< relref "/ChapterFour/0001~0099/0078.Subsets.md" >}})|Medium| O(n^2)| O(n)|❤️|66.2%|
|
|
|0079|Word Search|[Go]({{< relref "/ChapterFour/0001~0099/0079.Word-Search.md" >}})|Medium| O(n^2)| O(n^2)|❤️|37.5%|
|
|
|0089|Gray Code|[Go]({{< relref "/ChapterFour/0001~0099/0089.Gray-Code.md" >}})|Medium| O(n)| O(1)||51.0%|
|
|
|0090|Subsets II|[Go]({{< relref "/ChapterFour/0001~0099/0090.Subsets-II.md" >}})|Medium| O(n^2)| O(n)|❤️|49.5%|
|
|
|0093|Restore IP Addresses|[Go]({{< relref "/ChapterFour/0001~0099/0093.Restore-IP-Addresses.md" >}})|Medium| O(n)| O(n)|❤️|38.2%|
|
|
|0126|Word Ladder II|[Go]({{< relref "/ChapterFour/0100~0199/0126.Word-Ladder-II.md" >}})|Hard| O(n)| O(n^2)|❤️|24.0%|
|
|
|0131|Palindrome Partitioning|[Go]({{< relref "/ChapterFour/0100~0199/0131.Palindrome-Partitioning.md" >}})|Medium| O(n)| O(n^2)|❤️|53.2%|
|
|
|0211|Design Add and Search Words Data Structure|[Go]({{< relref "/ChapterFour/0200~0299/0211.Design-Add-and-Search-Words-Data-Structure.md" >}})|Medium| O(n)| O(n)|❤️|41.0%|
|
|
|0212|Word Search II|[Go]({{< relref "/ChapterFour/0200~0299/0212.Word-Search-II.md" >}})|Hard| O(n^2)| O(n^2)|❤️|37.7%|
|
|
|0216|Combination Sum III|[Go]({{< relref "/ChapterFour/0200~0299/0216.Combination-Sum-III.md" >}})|Medium| O(n)| O(1)|❤️|61.0%|
|
|
|0306|Additive Number|[Go]({{< relref "/ChapterFour/0300~0399/0306.Additive-Number.md" >}})|Medium| O(n^2)| O(1)|❤️|29.8%|
|
|
|0357|Count Numbers with Unique Digits|[Go]({{< relref "/ChapterFour/0300~0399/0357.Count-Numbers-with-Unique-Digits.md" >}})|Medium| O(1)| O(1)||49.2%|
|
|
|0401|Binary Watch|[Go]({{< relref "/ChapterFour/0400~0499/0401.Binary-Watch.md" >}})|Easy| O(1)| O(1)||48.8%|
|
|
|0526|Beautiful Arrangement|[Go]({{< relref "/ChapterFour/0500~0599/0526.Beautiful-Arrangement.md" >}})|Medium| O(n^2)| O(1)|❤️|62.3%|
|
|
|0784|Letter Case Permutation|[Go]({{< relref "/ChapterFour/0700~0799/0784.Letter-Case-Permutation.md" >}})|Medium| O(n)| O(n)||69.0%|
|
|
|0842|Split Array into Fibonacci Sequence|[Go]({{< relref "/ChapterFour/0800~0899/0842.Split-Array-into-Fibonacci-Sequence.md" >}})|Medium| O(n^2)| O(1)|❤️|37.0%|
|
|
|0980|Unique Paths III|[Go]({{< relref "/ChapterFour/0900~0999/0980.Unique-Paths-III.md" >}})|Hard| O(n log n)| O(n)||77.1%|
|
|
|0996|Number of Squareful Arrays|[Go]({{< relref "/ChapterFour/0900~0999/0996.Number-of-Squareful-Arrays.md" >}})|Hard| O(n log n)| O(n) ||48.6%|
|
|
|1079|Letter Tile Possibilities|[Go]({{< relref "/ChapterFour/1000~1099/1079.Letter-Tile-Possibilities.md" >}})|Medium| O(n^2)| O(1)|❤️|76.1%|
|
|
|1641|Count Sorted Vowel Strings|[Go]({{< relref "/ChapterFour/1600~1699/1641.Count-Sorted-Vowel-Strings.md" >}})|Medium||||75.2%|
|
|
|1655|Distribute Repeating Integers|[Go]({{< relref "/ChapterFour/1600~1699/1655.Distribute-Repeating-Integers.md" >}})|Hard||||40.1%|
|
|
|1659|Maximize Grid Happiness|[Go]({{< relref "/ChapterFour/1600~1699/1659.Maximize-Grid-Happiness.md" >}})|Hard||||36.0%|
|
|
|1681|Minimum Incompatibility|[Go]({{< relref "/ChapterFour/1600~1699/1681.Minimum-Incompatibility.md" >}})|Hard||||35.9%|
|
|
|1688|Count of Matches in Tournament|[Go]({{< relref "/ChapterFour/1600~1699/1688.Count-of-Matches-in-Tournament.md" >}})|Easy||||81.5%|
|
|
|------------|-------------------------------------------------------|-------| ----------------| ---------------|-------------|-------------|-------------|
|
|
|
|
|
|
----------------------------------------------
|
|
<div style="display: flex;justify-content: space-between;align-items: center;">
|
|
<p><a href="https://books.halfrost.com/leetcode/ChapterTwo/Dynamic_Programming/">⬅️上一页</a></p>
|
|
<p><a href="https://books.halfrost.com/leetcode/ChapterTwo/Depth_First_Search/">下一页➡️</a></p>
|
|
</div>
|