题解 | #合并表记录#

#include <iostream>
#include <map>
using namespace std;
int main()
{
    int N, a, b;
    map<int, int> num_map; // map中int类型默认value为0
    cin >> N;
    for (int i = 1; i <= N; i++)
    {
        cin >> a >> b;
        num_map[a] += b; // 若有相同key，则累加value
    }
    for (auto it = begin(num_map); it != num_map.end(); ++it)   //使用迭代器遍历map
    {
        cout << it->first << " " << it->second << endl; 
    }
    return 0;
}