#2165 - Smallest Value of the Rearranged Number

Medium • View on LeetCode • View on GitHub

Problem Description

You are given an integer num. Rearrange the digits of num such that its value is minimized and it does not contain any leading zeros.

Return the rearranged number with minimal value.

Note that the sign of the number does not change after rearranging the digits.

Solution

/**
 * @param {number} num
 * @return {number}
 */
var smallestNumber = function(num) {
  const isNegative = num < 0;
  const digits = Math.abs(num).toString().split('').map(Number);

  if (isNegative) {
    digits.sort((a, b) => b - a);
    return -parseInt(digits.join(''), 10);
  }

  digits.sort((a, b) => a - b);
  const firstNonZero = digits.findIndex(d => d !== 0);

  if (firstNonZero === -1) return 0;

  [digits[0], digits[firstNonZero]] = [digits[firstNonZero], digits[0]];
  return parseInt(digits.join(''), 10);
};