牛客拼数最大问题，不从结果出发那种做法

Question

一道算法题，来自牛客的拼数，示例结果都正确，但是最后题交错了，谢谢解答
题目：

#include <iostream>
using namespace std;
#include<map>
#include<vector>
#include<algorithm>
void GetMax(int num,vector<int> date1, vector<int> date2) {
    for (int i = 0; i<num; i++) {
        for (; date1[i] > 9;) {
            date1[i]=date1[i]/10;
        }
    }
    multimap<int, int> maxdate;
    for (int i = 0; i < num; i++) {
        maxdate.insert(pair<int, int>(date1[i],date2[i]));
    }
    multimap<int, int>::iterator it = maxdate.end();
    it--;
    for (; it != maxdate.begin(); it--) {
        cout << it->second;
    }
   
    cout<<it->second;
}
int main()
{
    int num,infor;
    vector<int>date1;
    vector<int>date2;
    cin >> num;
    for (int i = 0; i < num; i++) {
        cin >> infor;
        date1.push_back(infor);
        date2.push_back(infor);
    }
    GetMax(num, date1,date2);
    return 0;
}

Answer 1

对照