LeetCode: N Queens Solution

1/**
2 * @param {number} n
3 * @return {string[][]}
4 */
5var solveNQueens = function (n) {
6  const grid = Array.from({ length: n }, _ => Array(n).fill(0))
7  const res = []
8
9  const validate = (row, col) => {
10    for (let i = 0; i < row; i++) {
11      for (let j = 0; j < n; j++) {
12        if (
13          grid[i][j] &&
14          (col === j || Math.abs(col - j) === Math.abs(row - i))
15        ) {
16          return false
17        }
18      }
19    }
20    return true
21  }
22
23  const recursion = row => {
24    if (row === n) {
25      res.push(grid.map(row => row.map(col => (col ? "Q" : ".")).join("")))
26      return
27    }
28
29    for (let col = 0; col < n; col++) {
30      if (validate(row, col)) {
31        grid[row][col] = 1
32        recursion(row + 1)
33        grid[row][col] = 0
34      }
35    }
36  }
37
38  recursion(0)
39
40  return res
41}