Max Difference You Can Get From Changing an Integer | Leetcode 1432

class Solution {
public:
    int maxDiff(int num) {
        string s = to_string(num);
        string max_s = s;
        string min_s = s;
        int n = s.size();

        //Maximize number: The first digit<9 should be made 9
        for(int i=0;i<n;++i){
            if(s[i]!='9'){
                for(int j=0;j<n;++j)
                    if(max_s[j]==s[i])
                        max_s[j]='9';
                break;
            }
        }

        //Minimize number
        if(s[0]>'1'){
            for(int i=0;i<n;++i)
                if(min_s[i]==s[0])
                    min_s[i]='1';
        }else{
            //Find 1st digit>0 from index 1 to (n-1)
            for(int i=1;i<n;++i){
                if(s[i]>'1'){
                    for(int j=i;j<n;++j)
                        if(min_s[j]==s[i])
                            min_s[j]='0';
                    break;
                }
            }
        }
        return stoi(max_s)-stoi(min_s);
    }
};
/*
//JAVA
public class Solution {
    public int maxDiff(int num) {
        String s = Integer.toString(num);
        char[] maxChars = s.toCharArray();
        char[] minChars = s.toCharArray();
        int n = s.length();

        // Maximize number: The first digit < '9' should be made '9'
        for (int i = 0; i < n; ++i) {
            if (maxChars[i] != '9') {
                char target = maxChars[i];
                for (int j = 0; j < n; ++j) {
                    if (maxChars[j] == target) {
                        maxChars[j] = '9';
                    }
                }
                break;
            }
        }

        // Minimize number
        if (minChars[0] > '1') {
            char target = minChars[0];
            for (int i = 0; i < n; ++i) {
                if (minChars[i] == target) {
                    minChars[i] = '1';
                }
            }
        } else {
            // Find first digit > '0' from index 1 to (n-1)
            for (int i = 1; i < n; ++i) {
                if (minChars[i] > '1') {
                    char target = minChars[i];
                    for (int j = i; j < n; ++j) {
                        if (minChars[j] == target) {
                            minChars[j] = '0';
                        }
                    }
                    break;
                }
            }
        }

        int maxNum = Integer.parseInt(new String(maxChars));
        int minNum = Integer.parseInt(new String(minChars));
        return maxNum - minNum;
    }
}

#Python
class Solution:
    def maxDiff(self, num: int) -> int:
        s = str(num)
        max_s = list(s)
        min_s = list(s)
        n = len(s)

        # Maximize number: The first digit < '9' should be made '9'
        for i in range(n):
            if max_s[i] != '9':
                target = max_s[i]
                for j in range(n):
                    if max_s[j] == target:
                        max_s[j] = '9'
                break

        # Minimize number
        if min_s[0] > '1':
            target = min_s[0]
            for i in range(n):
                if min_s[i] == target:
                    min_s[i] = '1'
        else:
            # Find first digit > '0' from index 1 to (n-1)
            for i in range(1, n):
                if min_s[i] > '1':
                    target = min_s[i]
                    for j in range(i, n):
                        if min_s[j] == target:
                            min_s[j] = '0'
                    break

        max_num = int(''.join(max_s))
        min_num = int(''.join(min_s))
        return max_num - min_num
*/