题解 | #合并表记录#

#include<iostream>
#include<map>
using namespace std;
int main() {
    int n;
    cin >> n; 
    map<int, int> mp;    //使用map容器
    map<int, int>::iterator falg;    //map类型的迭代器
    for (int i = 0; i < n; i++) {
        int a, b;
        cin >> a;
        cin >> b;
        falg = mp.find(a);    //查找键a是否存在
        if (falg != mp.end()) {   //求和；
            mp[a] = falg->second + b;
        } else {        //新的键值对
            mp[a] = b;
        }
    }
    for (falg = mp.begin(); falg != mp.end(); falg++) { //打印
        cout << falg->first << " " << falg->second << endl;
    }
    return 0;
}