Utkarsh in Gardens

import java.util.*; import java.math.*; import java.lang.*; import java.io.*; class TestClass { static BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); static PrintWriter pw = new PrintWriter(new OutputStreamWriter(System.out)); public static void main(String args[] ) throws Exception { int n = Integer.parseInt(br.readLine()); long res = 0; int arr[][] = new int[n][n]; ArrayList<Integer> adjList[] = new ArrayList[n]; for(int i=0; i<n; i++) { adjList[i] = new ArrayList<Integer>(); } for(int i=0; i<n; i++) { adjList[i] = new ArrayList<Integer>(); String[] s = br.readLine().split(" "); for(int j=0; j<n; j++) { int z = Integer.parseInt(s[j]); if(z == 1) { adjList[i].add(j); } } } for(int i=0; i<n; i++) { for(int j=0; j<n; j++) { arr[i][j] = 0; } } // I dont understand the idea here for(int i=0; i<n; i++) { for(int j=0; j<adjList[i].size(); j++) { for(int k=j+1; k<adjList[i].size(); k++) { arr[adjList[i].get(j)][adjList[i].get(k)]++; } } } for(int i=0; i<n; i++) { for(int j=0; j<n; j++) { res += arr[i][j]*(arr[i][j] - 1); } } pw.println(res/4); pw.flush(); pw.close(); } }