Max Difference You Can Get From Changing an Integer

Description

You are given an integer num. You will apply the following steps exactly two times:

• Pick a digit x (0 <= x <= 9).
• Pick another digit y (0 <= y <= 9). The digit y can be equal to x.
• Replace all the occurrences of x in the decimal representation of num by y.
• The new integer cannot have any leading zeros, also the new integer cannot be 0.

Let a and b be the results of applying the operations to num the first and second times, respectively.

Return the max difference between a and b.

 

Example 1:

Input: num = 555
Output: 888
Explanation: The first time pick x = 5 and y = 9 and store the new integer in a.
The second time pick x = 5 and y = 1 and store the new integer in b.
We have now a = 999 and b = 111 and max difference = 888

Example 2:

Input: num = 9
Output: 8
Explanation: The first time pick x = 9 and y = 9 and store the new integer in a.
The second time pick x = 9 and y = 1 and store the new integer in b.
We have now a = 9 and b = 1 and max difference = 8

Example 3:

Input: num = 123456
Output: 820000

Example 4:

Input: num = 10000
Output: 80000

Example 5:

Input: num = 9288
Output: 8700

 

Constraints:

• 1 <= num <= 10^8

Solution(javascript)

/**
 * @param {number} num
 * @return {number}
 */
const maxDiff = function (num) {
  const arr = num.toString().split('')
  const num1 = arr.find(x => x !== '9')
  const max = arr.map(x => (x === num1 ? '9' : x)).join('')

  let num2 = 0
  if (arr[0] === '1') {
    num2 = arr.find(x => x !== '1' && x !== '0')
  } else {
    num2 = arr.find(x => x !== '0')
  }

  let min = 0
  if (arr[0] === num2) {
    min = arr.map(x => (x === num2 ? '1' : x)).join('')
  } else {
    min = arr.map(x => (x === num2 ? '0' : x)).join('')
  }
  return Number(max) - Number(min)
}