Merge pull request #2358 from pzppzz/master

feat: 0332重新安排行程 添加JavaScript版本 处理对象key无序问题 0051.N皇后 更简洁清晰的javascript版本
This commit is contained in:
程序员Carl
2023-12-11 10:01:37 +08:00
committed by GitHub
2 changed files with 130 additions and 54 deletions

View File

@ -453,60 +453,66 @@ func isValid(n, row, col int, chessboard [][]string) bool {
### Javascript
```Javascript
var solveNQueens = function(n) {
function isValid(row, col, chessBoard, n) {
for(let i = 0; i < row; i++) {
if(chessBoard[i][col] === 'Q') {
return false
}
}
for(let i = row - 1, j = col - 1; i >= 0 && j >= 0; i--, j--) {
if(chessBoard[i][j] === 'Q') {
return false
}
}
for(let i = row - 1, j = col + 1; i >= 0 && j < n; i--, j++) {
if(chessBoard[i][j] === 'Q') {
return false
}
}
return true
}
function transformChessBoard(chessBoard) {
let chessBoardBack = []
chessBoard.forEach(row => {
let rowStr = ''
row.forEach(value => {
rowStr += value
})
chessBoardBack.push(rowStr)
})
return chessBoardBack
}
let result = []
function backtracing(row,chessBoard) {
if(row === n) {
result.push(transformChessBoard(chessBoard))
return
}
for(let col = 0; col < n; col++) {
if(isValid(row, col, chessBoard, n)) {
chessBoard[row][col] = 'Q'
backtracing(row + 1,chessBoard)
chessBoard[row][col] = '.'
}
}
}
let chessBoard = new Array(n).fill([]).map(() => new Array(n).fill('.'))
backtracing(0,chessBoard)
return result
/**
* @param {number} n
* @return {string[][]}
*/
var solveNQueens = function (n) {
const ans = [];
const path = [];
const matrix = new Array(n).fill(0).map(() => new Array(n).fill("."));
// 判断是否能相互攻击
const canAttack = (matrix, row, col) => {
let i;
let j;
// 判断正上方和正下方是否有皇后
for (i = 0, j = col; i < n; i++) {
if (matrix[i][j] === "Q") {
return true;
}
}
// 判断正左边和正右边是否有皇后
for (i = row, j = 0; j < n; j++) {
if (matrix[i][j] === "Q") {
return true;
}
}
// 判断左上方是否有皇后
for (i = row - 1, j = col - 1; i >= 0 && j >= 0; i--, j--) {
if (matrix[i][j] === "Q") {
return true;
}
}
// 判断右上方是否有皇后
for (i = row - 1, j = col + 1; i >= 0 && j < n; i--, j++) {
if (matrix[i][j] === "Q") {
return true;
}
}
return false;
};
const backtrack = (matrix, row, col) => {
if (path.length === matrix.length) {
ans.push(path.slice());
return;
}
for (let i = row; i < matrix.length; i++) {
for (let j = col; j < matrix.length; j++) {
// 当前位置会导致互相攻击 继续下一轮搜索
if (canAttack(matrix, i, j)) {
continue;
}
matrix[i][j] = "Q";
path.push(matrix[i].join(""));
// 另起一行搜索 同一行只能有一个皇后
backtrack(matrix, i + 1, 0);
matrix[i][j] = ".";
path.pop();
}
}
};
backtrack(matrix, 0, 0);
return ans;
};
```

View File

@ -562,6 +562,7 @@ func findItinerary(tickets [][]string) []string {
```
### Javascript
```Javascript
var findItinerary = function(tickets) {
@ -605,6 +606,74 @@ var findItinerary = function(tickets) {
```
**javascript版本二 处理对象key无序问题**
```javascript
/**
* @param {string[][]} tickets
* @return {string[]}
*/
var findItinerary = function (tickets) {
const ans = ["JFK"];
let map = {};
// 整理每个站点的终点站信息
tickets.forEach((t) => {
let targets = map[t[0]];
if (!targets) {
targets = { [t[1]]: 0 };
map[t[0]] = targets;
}
targets[t[1]] = (targets[t[1]] || 0) + 1;
});
// 按照key字典序排序对象
const sortObject = (obj) => {
const newObj = {};
const keys = Object.keys(obj);
keys.sort((k1, k2) => (k1 < k2 ? -1 : 1));
keys.forEach((key) => {
if (obj[key] !== null && typeof obj[key] === "object") {
newObj[key] = sortObject(obj[key]);
} else {
newObj[key] = obj[key];
}
});
return newObj;
};
const backtrack = (tickets, targets) => {
if (ans.length === tickets.length + 1) {
return true;
}
const target = targets[ans[ans.length - 1]];
// 没有下一站
if (!target) {
return false;
}
// 或者在这里排序
// const keyList = Object.keys(target).sort((k1, k2) => (k1 < k2 ? -1 : 1));
const keyList = Object.keys(target);
for (const key of keyList) {
// 判断当前站是否还能飞
if (target[key] > 0) {
target[key]--;
ans.push(key);
// 对象key有序 此时的行程就是字典序最小的 直接跳出
if (backtrack(tickets, targets)) {
return true;
}
target[key]++;
ans.pop();
}
}
return false;
};
map = sortObject(map);
backtrack(tickets, map);
return ans;
};
```
### TypeScript
```typescript
@ -901,3 +970,4 @@ impl Solution {
<a href="https://programmercarl.com/other/kstar.html" target="_blank">
<img src="../pics/网站星球宣传海报.jpg" width="1000"/>
</a>