题解 | #合并表记录#

#include <iostream>
#include <unordered_map>
using namespace std;
#include <vector>
#include <algorithm>

struct PayRoll2{
    int key;
    int value;
};

int main() {
    int n;
    cin>>n;
    
    unordered_map<int, int> hashtable;
    vector<PayRoll2> vec;

    int a, b;
    while (cin >> a >> b) { // 注意 while 处理多个 case
        if(hashtable.count(a) == 0){
            hashtable[a] = b;
        }else{
            hashtable[a] += b;
        }
    }

    for(auto& [key, value]: hashtable){
        // cout<<key<<" "<<value<<endl;
        vec.push_back(PayRoll2{key, value});
    }
    sort(vec.begin(), vec.end(), [](PayRoll2 a, PayRoll2 b){
        return a.key < b.key;
    });

    for(auto & tmp:vec){
        cout<< tmp.key<<" "<<tmp.value<<endl;
    }
    return 0;
}
// 64 位输出请用 printf("%lld")