f0310.cpp

it is a usefull thing

//=====================================
// f0310.cpp
// 向量操作
//=====================================
#include<iostream>
#include<fstream>
#include<vector>
using namespace std;
//-------------------------------------
int main(){
  ifstream in("aaa.txt");
  vector<int> s;
  for(int a; in>>a; )
    s.push_back(a);
  int pare=0;
  for(int i=0; i<s.size()-1; ++i)
  for(int j=i+1; j<s.size(); ++j)
    if(s[i]==s[j]) pare++;
  cout<<pare<<"\n";
}//====================================