#2283 - Check if Number Has Equal Digit Count and Digit Value

Easy • View on LeetCode • View on GitHub

Problem Description

You are given a 0-indexed string num of length n consisting of digits.

Return true if for every index i in the range 0 <= i < n, the digit i occurs num[i] times in num, otherwise return false.

Solution

/**
 * @param {string} num
 * @return {boolean}
 */
var digitCount = function(num) {
  const frequency = new Array(10).fill(0);

  for (const digit of num) {
    frequency[digit]++;
  }

  for (let i = 0; i < num.length; i++) {
    if (frequency[i] !== Number(num[i])) {
      return false;
    }
  }

  return true;
};