排序4 统计工龄

题目：https://pintia.cn/problem-sets/1268384564738605056/problems/1291317697694580736
题解：https://blog.csdn.net/qq_40946921/article/details/99723044
代码：

#include<iostream>
#include<map>
using namespace std;
int main() {
    map<int, int> mp;
    int n, t;
    cin >> n;
    for (int i = 0; i < n; ++i) {
        cin >> t;
        mp[t]++;
    }
    for (auto& it : mp)
        cout << it.first << ":" << it.second << endl;
    return 0;
}