题解 | #合并表记录#

#include <functional>
#include <iostream>
#include <queue>
#include <unordered_map>
#include <vector>
using namespace std;
using LL = long long;

int main() {
    int n;
    while (cin >> n) {
        unordered_map<LL, LL> cnts;
        priority_queue<LL, vector<LL>, greater<>> index;
        int a, b;
        for (int i = 0; i < n; ++i) {
            cin >> a >> b;
            if (cnts.find(a) == cnts.end()) {
                index.push(a);
            }
            cnts[a] += b;
        }
        while (!index.empty()) {
            LL k = index.top();
            index.pop();
            printf("%lld %lld\n", k, cnts[k]);
        }
    }
}
// 64 位输出请用 printf("%lld")