1136. A Delayed Palindrome (20)

#include <iostream>
#include <algorithm>
#include <string>
using namespace std;

string s, s0;

void add(string &s, string &s0){
    int h = 0;
    for (int i = (int)s.length() - 1; i >= 0; i--) {
        s[i] = s[i] + s0[i] + h - '0';
        if(s[i] > '9'){ s[i] = s[i] - 10; h = 1;}
        else h = 0;
    }
    if (h) s = "1" + s;
}

int main() {
    cin >> s;
    s0 = s;
    reverse(s0.begin(), s0.end());
    if (s == s0) {
        printf("%s is a palindromic number.\n", s.c_str()); return 0;
    }else{
        for (int i = 0; i < 10; i++) {
            s0 = s;
            reverse(s.begin(), s.end());
            if(s == s0) {printf("%s is a palindromic number.", s.c_str()); return 0;}
            printf("%s + %s = ", s0.c_str(), s.c_str());
            add(s, s0);
            printf("%s\n", s.c_str());
        }
    }
    printf("Not found in 10 iterations.\n");
    return 0;
}