diff --git a/problems/0017.电话号码的字母组合.md b/problems/0017.电话号码的字母组合.md index 7040182f..94136565 100644 --- a/problems/0017.电话号码的字母组合.md +++ b/problems/0017.电话号码的字母组合.md @@ -420,6 +420,40 @@ var letterCombinations = function(digits) { }; ``` +## TypeScript + +```typescript +function letterCombinations(digits: string): string[] { + if (digits === '') return []; + const strMap: { [index: string]: string[] } = { + 1: [], + 2: ['a', 'b', 'c'], + 3: ['d', 'e', 'f'], + 4: ['g', 'h', 'i'], + 5: ['j', 'k', 'l'], + 6: ['m', 'n', 'o'], + 7: ['p', 'q', 'r', 's'], + 8: ['t', 'u', 'v'], + 9: ['w', 'x', 'y', 'z'], + } + const resArr: string[] = []; + function backTracking(digits: string, curIndex: number, route: string[]): void { + if (curIndex === digits.length) { + resArr.push(route.join('')); + return; + } + let tempArr: string[] = strMap[digits[curIndex]]; + for (let i = 0, length = tempArr.length; i < length; i++) { + route.push(tempArr[i]); + backTracking(digits, curIndex + 1, route); + route.pop(); + } + } + backTracking(digits, 0, []); + return resArr; +}; +``` + ## C ```c diff --git a/problems/0077.组合优化.md b/problems/0077.组合优化.md index 81b4304c..94608ec1 100644 --- a/problems/0077.组合优化.md +++ b/problems/0077.组合优化.md @@ -240,7 +240,29 @@ var combine = function(n, k) { }; ``` +TypeScript： + +```typescript +function combine(n: number, k: number): number[][] { + let resArr: number[][] = []; + function backTracking(n: number, k: number, startIndex: number, tempArr: number[]): void { + if (tempArr.length === k) { + resArr.push(tempArr.slice()); + return; + } + for (let i = startIndex; i <= n - k + 1 + tempArr.length; i++) { + tempArr.push(i); + backTracking(n, k, i + 1, tempArr); + tempArr.pop(); + } + } + backTracking(n, k, 1, []); + return resArr; +}; +``` + C: + ```c int* path; int pathTop; diff --git a/problems/0127.单词接龙.md b/problems/0127.单词接龙.md index 407596c0..584bcb2a 100644 --- a/problems/0127.单词接龙.md +++ b/problems/0127.单词接龙.md @@ -134,7 +134,29 @@ public int ladderLength(String beginWord, String endWord, List wordList) ``` ## Python - +``` +class Solution: + def ladderLength(self, beginWord: str, endWord: str, wordList: List[str]) -> int: + wordSet = set(wordList) + if len(wordSet)== 0 or endWord not in wordSet: + return 0 + mapping = {beginWord:1} + queue = deque([beginWord]) + while queue: + word = queue.popleft() + path = mapping[word] + for i in range(len(word)): + word_list = list(word) + for j in range(26): + word_list[i] = chr(ord('a')+j) + newWord = "".join(word_list) + if newWord == endWord: + return path+1 + if newWord in wordSet and newWord not in mapping: + mapping[newWord] = path+1 + queue.append(newWord) + return 0 +``` ## Go ## JavaScript diff --git a/problems/0134.加油站.md b/problems/0134.加油站.md index 1062a91c..1777faad 100644 --- a/problems/0134.加油站.md +++ b/problems/0134.加油站.md @@ -239,6 +239,30 @@ class Solution { ### Python ```python +# 解法1 +class Solution: + def canCompleteCircuit(self, gas: List[int], cost: List[int]) -> int: + n = len(gas) + cur_sum = 0 + min_sum = float('inf') + + for i in range(n): + cur_sum += gas[i] - cost[i] + min_sum = min(min_sum, cur_sum) + + if cur_sum < 0: return -1 + if min_sum >= 0: return 0 + + for j in range(n - 1, 0, -1): + min_sum += gas[j] - cost[j] + if min_sum >= 0: + return j + + return -1 +``` + +```python +# 解法2 class Solution: def canCompleteCircuit(self, gas: List[int], cost: List[int]) -> int: start = 0 diff --git a/problems/0141.环形链表.md b/problems/0141.环形链表.md index 0712a2a2..ddd83c94 100644 --- a/problems/0141.环形链表.md +++ b/problems/0141.环形链表.md @@ -106,6 +106,21 @@ class Solution: ## Go ```go +func hasCycle(head *ListNode) bool { + if head==nil{ + return false + } //空链表一定不会有环 + fast:=head + slow:=head //快慢指针 + for fast.Next!=nil&&fast.Next.Next!=nil{ + fast=fast.Next.Next + slow=slow.Next + if fast==slow{ + return true //快慢指针相遇则有环 + } + } + return false +} ``` ### JavaScript diff --git a/problems/0151.翻转字符串里的单词.md b/problems/0151.翻转字符串里的单词.md index 4865821a..d03de421 100644 --- a/problems/0151.翻转字符串里的单词.md +++ b/problems/0151.翻转字符串里的单词.md @@ -222,7 +222,44 @@ public: 效率： +```CPP +//版本二： +//原理同版本1，更简洁实现。 +class Solution { +public: + void reverse(string& s, int start, int end){ //翻转，区间写法：闭区间 [] + for (int i = start, j = end; i < j; i++, j--) { + swap(s[i], s[j]); + } + } + void removeExtraSpaces(string& s) {//去除所有空格并在相邻单词之间添加空格, 快慢指针。 + int slow = 0; //整体思想参考Leetcode: 27. 移除元素：https://leetcode-cn.com/problems/remove-element/ + for (int i = 0; i < s.size(); ++i) { // + if (s[i] != ' ') { //遇到非空格就处理，即删除所有空格。 + if (slow != 0) s[slow++] = ' '; //手动控制空格，给单词之间添加空格。slow != 0说明不是第一个单词，需要在单词前添加空格。 + while (i < s.size() && s[i] != ' ') { //补上该单词，遇到空格说明单词结束。 + s[slow++] = s[i++]; + } + } + } + s.resize(slow); //slow的大小即为去除多余空格后的大小。 + } + + string reverseWords(string s) { + removeExtraSpaces(s); //去除多余空格，保证单词之间之只有一个空格，且字符串首尾没空格。 + reverse(s, 0, s.size() - 1); + int start = 0; //removeExtraSpaces后保证第一个单词的开始下标一定是0。 + for (int i = 0; i <= s.size(); ++i) { + if (i == s.size() || s[i] == ' ') { //到达空格或者串尾，说明一个单词结束。进行翻转。 + reverse(s, start, i - 1); //翻转，注意是左闭右闭 []的翻转。 + start = i + 1; //更新下一个单词的开始下标start + } + } + return s; + } +}; +``` ## 其他语言版本 diff --git a/problems/0189.旋转数组.md b/problems/0189.旋转数组.md index 1efe9446..3ffed877 100644 --- a/problems/0189.旋转数组.md +++ b/problems/0189.旋转数组.md @@ -124,6 +124,19 @@ class Solution: ## Go ```go +func rotate(nums []int, k int) { + l:=len(nums) + index:=l-k%l + reverse(nums) + reverse(nums[:l-index]) + reverse(nums[l-index:]) +} +func reverse(nums []int){ + l:=len(nums) + for i:=0;i n) return; + if (tempArr.length === k) { + if (sum === n) { + resArr.push(tempArr.slice()); + } + return; + } + for (let i = startIndex; i <= 9 - (k - tempArr.length) + 1; i++) { + tempArr.push(i); + backTracking(k, n, sum + i, i + 1, tempArr); + tempArr.pop(); + } + } + backTracking(k, n, 0, 1, []); + return resArr; +}; +``` + ## C ```c diff --git a/problems/0332.重新安排行程.md b/problems/0332.重新安排行程.md index 01f81c4d..041a7f03 100644 --- a/problems/0332.重新安排行程.md +++ b/problems/0332.重新安排行程.md @@ -342,6 +342,64 @@ class Solution: return path ``` +### Go +```go +type pair struct { + target string + visited bool +} +type pairs []*pair + +func (p pairs) Len() int { + return len(p) +} +func (p pairs) Swap(i, j int) { + p[i], p[j] = p[j], p[i] +} +func (p pairs) Less(i, j int) bool { + return p[i].target < p[j].target +} + +func findItinerary(tickets [][]string) []string { + result := []string{} + // map[出发机场] pair{目的地,是否被访问过} + targets := make(map[string]pairs) + for _, ticket := range tickets { + if targets[ticket[0]] == nil { + targets[ticket[0]] = make(pairs, 0) + } + targets[ticket[0]] = append(targets[ticket[0]], &pair{target: ticket[1], visited: false}) + } + for k, _ := range targets { + sort.Sort(targets[k]) + } + result = append(result, "JFK") + var backtracking func() bool + backtracking = func() bool { + if len(tickets)+1 == len(result) { + return true + } + // 取出起飞航班对应的目的地 + for _, pair := range targets[result[len(result)-1]] { + if pair.visited == false { + result = append(result, pair.target) + pair.visited = true + if backtracking() { + return true + } + result = result[:len(result)-1] + pair.visited = false + } + } + return false + } + + backtracking() + + return result +} +``` + ### C语言 ```C