Find all the quadruples [a, b, c, d] where a^3 + b^3 = c^3 + d^3 when 1 <= a, b, c or d <= 10000 [closed]

Answer 1

Using Hashmap (O(n^2) solution):

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import static java.lang.Math.pow;

/**
 * Created by Anup on 10-10-2016.
 */

class Pair {
    int a;
    int b;

    Pair(int x, int y) {
        a = x;
        b = y;
    }
}

public class FindCubePair {
    public static void main(String[] args) {
        HashMap> hashMap = new HashMap<>();
        int n = 100000;

        for(int i = 1; i <= n; i++) {
            for(int j = 1; j <= n; j++) {
                long sum = (long) (pow(i, 3) + pow(j, 3));

                if(hashMap.containsKey(sum)) {
                    List list = hashMap.get(sum);
                    for(Pair p : list) {
                        System.out.println(i + " " + j + " " + p.a + " " + p.b);
                    }
                } else {
                    ArrayList list = new ArrayList<>();
                    hashMap.put(sum, list);
                }

                hashMap.get(sum).add(new Pair(i, j));
            }
        }
    }
}

Unfortunately, the value of integers printed does not even reach 1000 on my computer due to resource limitation.