leetcode/valid-parentheses.js at main · omersakmar/leetcode · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
/*

Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.

An input string is valid if:

    Open brackets must be closed by the same type of brackets.
    Open brackets must be closed in the correct order.
    Every close bracket has a corresponding open bracket of the same type.


Example 1:

Input: s = "()"
Output: true

Example 2:

Input: s = "()[]{}"
Output: true

Example 3:

Input: s = "(]"
Output: false
*/

const isValid = (s) => {
  if (s.length % 2 !== 0) return false;

  const stack = [];
  const map = new Map([
    ['(', ')'],
    ['[', ']'],
    ['{', '}']
  ]);

  for (let i = 0 ; i < s.length ; i += 1) {
    if (map.has(s[i])) {
      stack.push(map.get(s[i]));
    } else if (s[i] !== stack.pop()) {
      return false;
    }
  }
  return stack.length === 0;
};