Java: Test whether there are two integers x and y

Last update on May 13 2025 12:59:14 (UTC/GMT +8 hours)

Sum of Two Squares

Write a Java program to test whether there are two integers x and y such that x^2 + y^2 is equal to a given positive number.

Visual Presentation:

Sample Solution:

Java Code:

import java.util.*;

// Main class for the solution
public class Solution {  

    // Main method to execute the solution
    public static void main(String[] args) {
        // Create a Scanner object for user input
        Scanner in = new Scanner(System.in);	
        
        // Prompt the user to input a positive integer
        System.out.print("Input a positive integer: ");
        
        // Read the user input as an integer
        int n = in.nextInt(); 

        // Check if the input is a positive integer
        if (n > 0) {
            // Display the result of the sum_of_square_numbers function
            System.out.print("Is " + n + " sum of two square numbers? " + sum_of_square_numbers(n));
        }  		
    }

    // Function to check if a number is the sum of two square numbers
    public static boolean sum_of_square_numbers(int n) {
        // Initialize two pointers, left_num and right_num
        int left_num = 0, right_num = (int) Math.sqrt(n);

        // Iterate until the left_num pointer is less than or equal to the right_num pointer
        while (left_num <= right_num) {
            // Check if the sum of squares of left_num and right_num is equal to n
            if (left_num * left_num + right_num * right_num == n) {
                return true;
            } else if (left_num * left_num + right_num * right_num < n) {
                // Increment left_num if the current sum is less than n
                left_num++;
            } else {
                // Decrement right_num if the current sum is greater than n
                right_num--;
            }
        }

        // If no pair of square numbers sum up to n, return false
        return false;
    }
} 

Sample Output:

Input a positive integer:  25
Is 25 sum of two square numbers? true

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Java program to determine if a given number can be expressed as the sum of three square numbers.
• Write a Java program to count the number of distinct pairs of squares that sum up to a specified number.
• Write a Java program to list all pairs of integers whose squares add up to a given number.
• Write a Java program to test whether a positive number can be represented as the sum of two cube numbers.

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