fork download
copy 
  1. #include <iostream>
  2. using namespace std;
  3. #include <bits/stdc++.h>
  4. int main() {
  5. 	// your code goes here
  6. 	int  n;
  7. 	cin>>n;
  8. 	int arr[n];
  9. 	int i=0;
  10. 	while(i<n)
  11. 	 {
  12. 	 	cin>>arr[i];
  13. 	 	i++;
  14. 	 }
  15.  
  16.  
  17.       unordered_map<int,int>freq;
  18.       for(int l=3;l<n;l++)
  19.        {
  20.        	freq[arr[l]]++;
  21.        }
  22.        int count=0;
  23.        for(int i=0;i<n;i++)
  24.         {
  25.         	for(int j=i+1;j<n;j++)
  26.         	 {
  27.         	 	for(int k=j+1;k<n;k++)
  28.         	 	 {
  29.         	 	 	int g=arr[i]+arr[j]+arr[k];
  30.         	 	 	count=count+freq[-g];
  31.         	 	 	int remove=arr[k+1];
  32.         	 	 	freq[remove]=0;
  33.         	 	 }
  34.         	 }
  35.         }
  36.  
  37.  
  38.  
  39. 	  cout<<count;
  40.  
  41. 	return 0;
  42. }
Success #stdin #stdout 0.01s 5288KB
comments (?)
stdin
copy 
7
1 2 3 4 -1 -2 -2
stdout
copy 
2
https://ideone.com/rlRB4m
language:
C++ (gcc 8.3)
created:
7 hours ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!