solution.ts

/*
 * @lc app=leetcode id=394 lang=javascript
 *
 * [394] Decode String
 */

// @lc code=start
/**
 * @param {string} s
 * @return {string}
 */
const decodeString = (s: string): string => {
  // * ['48 ms', '88.89 %', '33.8 MB', '83.33 %']

  const resultArr: string[] = [''];
  const timesStack: number[] = [];
  let times = 0;

  for (let i = 0; i < s.length; i++) {
    const char = s[i];

    if (!Number.isNaN(Number(char))) {
      times = 10 * times + Number(char);
    } else if (char === '[') {
      timesStack.push(times);
      resultArr.push('');
      times = 0;
    } else if (char === ']') {
      const times = timesStack.pop()!;
      const subStr = resultArr.pop()!;
      resultArr[resultArr.length - 1] += subStr.repeat(times);
    } else {
      resultArr[resultArr.length - 1] += char;
    }
  }

  return resultArr[0];
};
// @lc code=end

export { decodeString };