#2048 - Next Greater Numerically Balanced Number

Medium • View on LeetCode • View on GitHub

Hash Table Math Counting Enumeration Backtracking

Problem Description

An integer x is numerically balanced if for every digit d in the number x, there are exactly d occurrences of that digit in x.

Given an integer n, return the smallest numerically balanced number strictly greater than n.

Solution

/**
 * @param {number} n
 * @return {number}
 */
var nextBeautifulNumber = function(n) {
  let candidate = n + 1;
  while (candidate <= 10000000) {
    if (isBalanced(candidate)) return candidate;
    candidate++;
  }

  return -1;

  function isBalanced(num) {
    const freq = new Array(10).fill(0);
    const str = num.toString();

    for (const digit of str) {
      freq[digit]++;
    }

    for (const digit of str) {
      if (freq[digit] !== parseInt(digit)) return false;
    }

    return true;
  }
};