PAT 1038. Recover the Smallest Number

#include <iostream>

#include <cstdlib>

#include <vector>

#include <algorithm>



using namespace std;



bool mycmp(const string& a, const string& b) {

    string ta = a + b;

    string tb = b + a;

    

    int len = ta.length();

    

    for (int i=0; i<len; i++) {

        if (ta[i] > tb[i]) {

            return false;

        } else if (ta[i] < tb[i]){

            return true;

        }

    }

    return true;

}



bool print_no_leading_zero(string &n) {

    int len = n.length();

    bool full_zero = true;

    int i;

    for (i=0; i<len; i++) {

        if (n[i] != '0') {

            full_zero = false;

            break;

        }

    }

    while (i<len) {

        cout<<n[i++];

    }

    return full_zero;

}



int main() {

    string is;

    int N = 0;

    cin>>N;

    

    vector<string> segs(N);

    for (int i=0; i<N; i++) {

        cin>>segs[i];

    }

    

    int len = segs.size();



    sort(segs.begin(), segs.end(), mycmp);

    

    bool zero = true;

    if (len > 0) {

        for (int i=0; i<len; i++) {

            if (zero) {

                zero = print_no_leading_zero(segs[i]);

            } else {

                cout<<segs[i];

            }

        }

        

    } 

    if (len < 1 || zero) {

        cout<<0;

    }

    cout<<endl;

    return 0;

}

要不是以前做过还是想不到的