import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

public class isSquareFul {

public static void main(String[] args) {

int[] arr = {1,17,8};

System.out.println(permut(arr));

}

private static int count = 0;

public static int permut(int[] nums){

//List<List<Integer>> res = new ArrayList<>();

if(nums.length == 0 || nums == null) return count;

Arrays.sort(nums);

boolean[] used = new boolean[nums.length];

List<Integer> permutations = new ArrayList<>();

helper(permutations,nums,used,-1);

return count;

}

private static boolean isSquare(int a, int b){

double res = Math.sqrt(a+b);

boolean finalres = (res - Math.floor(res)) == 0;

return finalres;

}

private static void helper(List<Integer> temp, int[] nums, boolean[] used, int lastNumb) {

if (temp.size() == nums.length) count++;

else {

for (int i = 0; i < nums.length; i++) {

if(used[i]) continue;

if(lastNumb!=-1){

if (isSquare(nums[i],lastNumb)==false)

continue;

}

used[i] = true;

temp.add(nums[i]);

helper(temp,nums,used,lastNumb);

temp.remove(temp.size()-1);

used[i] = false;

while(i+1<nums.length && nums[i] == nums[i+1])

++i;

}

}

}

}