CodeForces 518A Vitaly and Strings (水题，字符串)

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <set>
#include <cstring>
#include <cmath>
#include <map>
#include <cctype>

using namespace std;
const int maxn = 1000 + 5;
string s, t;

int main(){
    while(cin >> s >> t){
        int n = s.size();
        int cnt = 0;
        ++s[n-1];
        if(s[n-1] > 'z'){ s[n-1] = 'a';  cnt = 1; }
        for(int i = n-2; i >= 0; --i){
            s[i] += cnt;
            if(s[i] > 'z'){ s[i] = 'a';  cnt = 1; }
            else  cnt = 0;
        }
        if(s == t)  puts("No such string");
        else  cout << s << endl;

    }
    return 0;
}