freeCodeCamp/guide/english/certifications/coding-interview-prep/rosetta-code/balanced-brackets/index.md

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Balanced brackets

Balanced brackets

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Basic Solution

function isBalanced(str) {
  if (str === '') return true;

  str = str.split('');
  let stack = [];
  for (let i = 0; i < str.length; i++) {
    if (str[i] === '[') {
      stack.push('[');
    } else if (str[i] === ']' && stack[stack.length - 1] === '[') {
      stack.pop();
    }
  }
  return stack.length === 0;
}

Code Explanation

• Split the input string into individual characters & loop over them.
• Push every [ into a stack.
• Check if the item stored on the stack is [ when a ] occurs. This makes it a pair & [ can be removed from the stack.
• The brackets are balanced if there is no item present in the stack.