README_EN.md

1432. Max Difference You Can Get From Changing an Integer

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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

 

Constraints:

• 1 <= num <= 10⁸

Solutions

Python3

class Solution:
    def maxDiff(self, num: int) -> int:
        a, b = str(num), str(num)
        for c in a:
            if c != '9':
                a = a.replace(c, '9')
                break
        for i, c in enumerate(b):
            if i == 0:
                if c != '1':
                    b = b.replace(c, '1')
                    break
            else:
                if c != '0' and c != b[0]:
                    b = b.replace(c, '0')
                    break
        return int(a) - int(b)

Java

class Solution {
    public int maxDiff(int num) {
        String a = String.valueOf(num);
        String b = String.valueOf(num);
        for (char c : a.toCharArray()) {
            if (c != '9') {
                a = a.replaceAll(String.valueOf(c), "9");
                break;
            }
        }
        for (int i = 0; i < b.length(); ++i) {
            char c = b.charAt(i);
            if (i == 0) {
                if (c != '1') {
                    b = b.replaceAll(String.valueOf(c), "1");
                    break;
                }
            } else {
                if (c != '0' && c != b.charAt(0)) {
                    b = b.replaceAll(String.valueOf(c), "0");
                    break;
                }
            }
        }
        return Integer.parseInt(a) - Integer.parseInt(b);
    }
}

Go

func maxDiff(num int) int {
	a, b := num, num
	s := strconv.Itoa(num)
	for i := range s {
		if s[i] != '9' {
			a, _ = strconv.Atoi(strings.ReplaceAll(s, string(s[i]), "9"))
			break
		}
	}
	if s[0] > '1' {
		b, _ = strconv.Atoi(strings.ReplaceAll(s, string(s[0]), "1"))
	} else {
		for i := 1; i < len(s); i++ {
			if s[i] != '0' && s[i] != s[0] {
				b, _ = strconv.Atoi(strings.ReplaceAll(s, string(s[i]), "0"))
				break
			}
		}
	}
	return a - b
}

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