借放一下程式碼，這題除了long long要注意其他都還好 

#include <iostream> //AC e465 f605 i399 k918 k900 k920
#include <vector>
#include <algorithm>
#define fast_as_a_fuckboy ios_base::sync_with_stdio(0); cin.tie(0); 
using namespace std;

int main(){
  fast_as_a_fuckboy
  long long int a, b, ans;
  vector<pair<int,int>> p;
  while(cin >> a >> b){
    p.push_back({a,b});
    ans += (a*b);
  }
  sort(p.begin(),p.end());
  reverse(p.begin(),p.end());
  for(int i = 0;i < p.size();i++){
    cout << p[i].first << "元鈔票共有" << p[i].second << "張\n";
  }
  cout << "總共有" << ans << "元";
}