题解 | #合并表记录# CPP

#include <iostream>
#include <map>

using namespace std;

int main() {
    map<int, int> map_num;  
    int n;
    cin >> n;
    int index, value;
    for (int i = 0; i < n; ++i) {
        cin >> index >> value;
        if (!map_num.count(index)) {
            map_num[index] = value;
        } else {
            map_num[index] += value;
        }
    }
    for (auto entry : map_num) {
        cout << entry.first << " ";
        cout << entry.second << endl;
    }
    return 0;
}