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Brackets (Lesson 7)

Instructions​

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 ")".

Translate to Korean​

괄호를 열고 닫을 떄 수가 맞게 모두 닫히면 1을 반환하고 그렇지 않으면 0을 반환한다.

ex)
A[0] = 4
-> (-4,0), (0, 4)

Solution​

function solution(S) {
  const START_BRACKET_OBJ = {
    '[': ']',
    '{': '}',
    '(': ')',
  };

  const splitS = S.split('');
  const bracketStack = [];

  for (let i = 0, splitSLength = splitS.length; i < splitSLength; i++) {
    const bracket = splitS[i];

    if (START_BRACKET_OBJ[bracket]) {
      bracketStack.push(bracket);
    } else {
      const popBracket = bracketStack.pop();

      if (START_BRACKET_OBJ[popBracket] !== bracket) {
        return 0;
      }
    }
  }
  return bracketStack.length ? 0 : 1;
}

References​