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1432. 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

 

Constraints:

  • 1 <= num <= 108

Solutions

Solution 1

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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
        if b[0] != "1":
            b = b.replace(b[0], "1")
        else:
            for c in b[1:]:
                if c not in "01":
                    b = b.replace(c, "0")
                    break
        return int(a) - int(b)

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

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class Solution {
public:
    int maxDiff(int num) {
        auto replace = [](string& s, char a, char b) {
            for (auto& c : s) {
                if (c == a) {
                    c = b;
                }
            }
        };
        string a = to_string(num);
        string b = a;
        for (int i = 0; i < a.size(); ++i) {
            if (a[i] != '9') {
                replace(a, a[i], '9');
                break;
            }
        }
        if (b[0] != '1') {
            replace(b, b[0], '1');
        } else {
            for (int i = 1; i < b.size(); ++i) {
                if (b[i] != '0' && b[i] != '1') {
                    replace(b, b[i], '0');
                    break;
                }
            }
        }
        return stoi(a) - stoi(b);
    }
};

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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] != '1' {
                b, _ = strconv.Atoi(strings.ReplaceAll(s, string(s[i]), "0"))
                break
            }
        }
    }
    return a - b
}

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