https://leetcode.com/problems/generate-parentheses/

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
/**
 * @param {number} n
 * @return {string[]}
 */
const generateParenthesis = (n) => {
    let ans = []
    backtrack(ans, n)
    return ans
}

const backtrack = (ans, n, open = 0, close = 0, s = '') => {
    if (s.length === n * 2) {
        ans.push(s)
        return
    }
    if (open < n) {
        backtrack(ans, n, open + 1, close, s + '(')
    }
    if (close < open) {
        backtrack(ans, n, open, close + 1, s + ')')
    }
}