1881

class Solution {
public:
    string maxValue(string n, int x) {
        string ans;
        if(n[0] == '-'){
            ans += '-';
            bool added = false;
            for(char ch: n){
                if(ch == '-') continue;
                if(ch-'0' > x && !added){
                    ans += ('0'+x);
                    added = true;
                }
                ans += ch;
            }
            if(!added)
                ans += ('0'+x);
        }
        else{
            bool added = false;
            for(char ch: n){
                if(ch-'0' < x && !added){
                    ans += ('0'+x);
                    added = true;
                }
                ans += ch;
            }
            if(!added)
                ans += ('0'+x);
        }
        return ans;
    }
};