题解 | #合并表记录#C++

一个数组记录出现的键
一个无序map记录键对应的值的累计

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


int main() {
    int n;
    cin >> n;
    vector<int> arr;
    unordered_map<int, int> map1;

    while (n-- > 0) {
        int key, val;
        cin >> key >> val;
        if (map1.count(key) == 0) {
            map1[key] = val;
            arr.push_back(key);
        }
        else {
            map1[key] += val;
        }

    }
    sort(arr.begin(), arr.end());
    for (int i = 0; i < arr.size(); ++i) {
        cout << arr[i] << " " << map1[arr[i]] << endl;
    }


    return 0;
}