LeetCode: Longest Valid Parentheses Solution

Approach

Highlight valid parentheses and find max length

Implementation

1function Stack() {
2  const stack = []
3
4  this.push = function (el) {
5    stack.push(el)
6  }
7
8  this.pop = function () {
9    return stack.pop()
10  }
11
12  this.peek = function () {
13    return stack[stack.length - 1]
14  }
15
16  this.isEmpty = function () {
17    return stack.length === 0
18  }
19}
20
21/**
22 * @param {string} s
23 * @return {number}
24 */
25var longestValidParentheses = function (s) {
26  const stack = new Stack()
27  s = s.split("")
28  for (let i = 0; i < s.length; i++) {
29    if (s[i] === "(") {
30      stack.push(i)
31    } else if (s[i] === ")" && s[stack.peek()] === "(") {
32      s[stack.peek()] = s[i] = "*"
33      stack.pop()
34    }
35  }
36  return Math.max.apply(
37    null,
38    s
39      .join("")
40      .split(/[\(\)]/g)
41      .filter(Boolean)
42      .map(sub => sub.length)
43      .concat(0)
44  )
45}