Valid Parentheses

Problem Description

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

An input string is valid if:

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

Example 1:

Example 2:

Example 3:

Example 4:

Example 5:

Constraints:

• 1 <= s.length <= 104
• s consists of parentheses only '()[]{}'.

Solution (JavaScript)

/**
 * @param {string} s
 * @return {boolean}
 */
var isValid = function(s) {
    const map = {
        ')': '(',
        ']': '[',
        '}': '{'
    };
    
    s = s.split('');
    let t = [];
    
    while(s.length) {
        if (!map[s[0]]) {
            t.push(s[0]);
            s.splice(0, 1)
        } else if (t.length && t[t.length - 1] === map[s[0]]) {
            t.splice(t.length - 1, 1);
            s.splice(0, 1);
        } else {
            return false;
        }
    }
    
    if(t.length) return false;
    
    return true;
};