brackets.js

// A string S consisting of N characters is considered to be properly nested if any of the following conditions is true:

// S is empty;
// S has the form "(U)" or "[U]" or "{U}" where U is a properly nested string;
// S has the form "VW" where V and W are properly nested strings.
// For example, the string "{[()()]}" is properly nested but "([)()]" is not.

// Write a function:

// class Solution { public int solution(String S); }

// that, given a string S consisting of N characters, returns 1 if S is properly nested and 0 otherwise.

// For example, given S = "{[()()]}", the function should return 1 and given S = "([)()]", the function should return 0, as explained above.

// Write an efficient algorithm for the following assumptions:

// N is an integer within the range [0..200,000];
// string S consists only of the following characters: "(", "{", "[", "]", "}" and/or ")".

console.log(solution("{[()()]}"));
function solution(S){
    var brackets = {
        "{": "}",
        "(": ")",
        "[": "]"
    }

    var closedBrackets = ["}", ")", "]"]
    var array = [];
    
    for (var i =0; i < S.length; i++) {
        if (brackets[S[i]] !== undefined) {
            array.push(S[i])
        } else if (brackets[array[array.length -1]] === S[i]) {
            array.pop()
        } else if (closedBrackets.indexOf(S[i]) !== -1) {
        	return 0
        }
    }
    return array.length === 0 ? 1 : 0
}