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; }