C++ 统计自然数出现次数并排序输出

#include <iostream>
#include <map>
using namespace std;

int main() {
    int n;
    cin >> n;
    
    map<int, int> countMap;
    
    for (int i = 0; i < n; i++) {
        int num;
        cin >> num;
        countMap[num]++;
    }
    
    for (auto it = countMap.begin(); it != countMap.end(); it++) {
        cout << it->first << ' ' << it->second << endl;
    }
    
    return 0;
}