코딜리티 - Brackets (javascript)

Task description

 

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:

 

function solution(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 ")".

 

풀이

 

function solution(S) {
    const s = [];

    [...S].forEach(v => {
        if (!s.length) s.push(v);
        else {
            const top = s[s.length - 1];

            if (top == '(' && v == ')') {
                s.pop();
            } else if (top == '['  && v == ']') {
                s.pop();
            } else if (top == '{'  && v == '}') {
                s.pop();
            } else {
                s.push(v);
            }
        }

    })

    return s.length ? 0 : 1;
}