C++ 解法, 执行用时: 2ms, 内存消耗: 380KB, 提交时间: 2020-10-31

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

int main(void)
{
    int n;
    string strnub;
    while (cin >> n >> strnub)
    {
        vector<int> record(10, 0);
        for (int i = 0; i < strnub.size(); i++)
        {
            if (record[strnub[i] - '0'] != 0)
            {
                string tmp = strnub.substr(i++, 2);
                cout << tmp << " ";
            }
            else
            {
                cout << strnub[i] << " ";
                record[strnub[i] - '0']++;
            }
        }
        cout << endl;
    }
    return 0;
}

C++14 解法, 执行用时: 2ms, 内存消耗: 380KB, 提交时间: 2020-08-15

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

int main(void)
{
    int n;
    string strnub;
    while (cin >> n >> strnub)
    {
        vector<int> record(10, 0);
        for (int i = 0; i < strnub.size(); i++)
        {
            if (record[strnub[i] - '0'] != 0)
            {
                string tmp = strnub.substr(i++, 2);
                cout << tmp << " ";
            }
            else
            {
                cout << strnub[i] << " ";
                record[strnub[i] - '0']++;
            }
        }
        cout << endl;
    }
    return 0;
}