Freight trains

input/code.cpp: In function 'bool comparator(std::string&, std::string&)':
input/code.cpp:8:19: warning: comparison of integer expressions of different signedness: 'int' and 'const long unsigned int' [-Wsign-compare]
    8 |     for (int i=0;i<min(s1.size(), s2.size()); i++){
      |                  ~^~~~~~~~~~~~~~~~~~~~~~~~~~

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

bool comparator(string &s1, string &s2){
    for (int i=0;i<min(s1.size(), s2.size()); i++){
        if (s1[i]<s2[i]){
            return true;
        } else if (s1[i]>s2[i]){
            return false;
        }
    }
    if (s1.size()==s2.size()){
        return true;
    }

    if (s1.size()>s2.size()){
        if (s1[s2.size()]<=s2[0]){
            return true;
        } else {
            return false;
        }
    } else {
        if (s2[s1.size()]<=s1[0]){
            return false;
        } else {
            return true;
        }
    }
}

int main(){
    int n;
    cin >> n;
    vector<string> s(n);

    for (int i=0;i<n;i++){
        cin >> s[i];
    }

    sort(s.begin(), s.end(), comparator);

    for (const auto& str: s){
        cout << str;
    }
    cout << '\n';
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED

Test 31

Verdict: WRONG ANSWER

Test 32

Verdict: WRONG ANSWER

Test 33

Verdict: ACCEPTED

Test 34

Verdict: WRONG ANSWER

Test 35

Verdict: ACCEPTED

Test 36

Verdict: ACCEPTED

Test 37

Verdict: WRONG ANSWER

Test 38

Verdict: ACCEPTED

Test 39

Verdict: WRONG ANSWER

Test 40

Verdict: WRONG ANSWER

Test 41

Verdict: WRONG ANSWER

Test 42

Verdict: WRONG ANSWER

Test 43

Verdict: WRONG ANSWER

Test 44

Verdict: WRONG ANSWER

Test 45

Verdict: WRONG ANSWER

Test 46

Verdict: WRONG ANSWER

Test 47

Verdict: WRONG ANSWER

Test 48

Verdict: ACCEPTED

Test 49

Verdict: WRONG ANSWER

Test 50

Verdict: WRONG ANSWER

Test 51

Verdict: WRONG ANSWER

Test 52

Verdict: WRONG ANSWER

Test 53

Verdict: WRONG ANSWER

Test 54

Verdict: WRONG ANSWER

Test 55

Verdict: WRONG ANSWER

Test 56

Verdict: WRONG ANSWER

Test 57

Verdict: WRONG ANSWER

Test 58

Verdict: WRONG ANSWER

Test 59

Verdict: WRONG ANSWER

Test 60

Verdict: WRONG ANSWER

Test 61

Verdict: WRONG ANSWER

Test 62

Verdict: WRONG ANSWER

Test 63

Verdict: WRONG ANSWER

Test 64

Verdict: WRONG ANSWER

Test 65

Verdict: WRONG ANSWER

Test 66

Verdict: WRONG ANSWER

Test 67

Verdict: WRONG ANSWER

Test 68

Verdict: WRONG ANSWER

Test 69

Verdict: WRONG ANSWER

Test 70

Verdict: WRONG ANSWER

Test 71

Verdict: WRONG ANSWER