Merge branch 'master' of github.com:youngyangyang04/leetcode-master

This commit is contained in:
programmercarl
2022-04-12 22:23:38 +08:00
9 changed files with 250 additions and 1 deletions

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@ -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
```c ```c

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@ -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:
```c ```c
int* path; int* path;
int pathTop; int pathTop;

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@ -134,7 +134,29 @@ public int ladderLength(String beginWord, String endWord, List<String> wordList)
``` ```
## Python ## 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 ## Go
## JavaScript ## JavaScript

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@ -239,6 +239,30 @@ class Solution {
### Python ### Python
```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: class Solution:
def canCompleteCircuit(self, gas: List[int], cost: List[int]) -> int: def canCompleteCircuit(self, gas: List[int], cost: List[int]) -> int:
start = 0 start = 0

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@ -106,6 +106,21 @@ class Solution:
## Go ## Go
```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 ### JavaScript

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@ -222,7 +222,44 @@ public:
效率: 效率:
<img src='https://code-thinking.cdn.bcebos.com/pics/151_翻转字符串里的单词.png' width=600> </img></div> <img src='https://code-thinking.cdn.bcebos.com/pics/151_翻转字符串里的单词.png' width=600> </img></div>
```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 ## 其他语言版本

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@ -124,6 +124,19 @@ class Solution:
## Go ## Go
```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<l/2;i++{
nums[i],nums[l-1-i]=nums[l-1-i],nums[i]
}
}
``` ```
## JavaScript ## JavaScript

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@ -396,6 +396,30 @@ var combinationSum3 = function(k, n) {
}; };
``` ```
## TypeScript
```typescript
function combinationSum3(k: number, n: number): number[][] {
const resArr: number[][] = [];
function backTracking(k: number, n: number, sum: number, startIndex: number, tempArr: number[]): void {
if (sum > 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
```c ```c

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@ -342,6 +342,64 @@ class Solution:
return path 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语言
```C ```C