Perfect Square

/*
 * Problem : Check if a number is a perfect square.
 * Input   : One integer.
 * Output  : true or false.
 * Approach: Take the square root and test the root.
 * Time    : O(1)
 * Space   : O(1)
 * Java    : 8 or newer.
 */
import java.util.Scanner;

public class Main {
    // This method receives a number and returns true if the number is a perfect square.
    static boolean isPerfectSquare(long number) {
        // Step 1: Negative numbers are never perfect squares.
        if (number < 0) {
            return false;
        }

        // Step 2: Take the square root and round it to the nearest whole number. Example: sqrt(16) = 4.
        long root = Math.round(Math.sqrt(number));

        // Step 3: Multiply the root by itself. The number is a perfect square only if we get the number back.
        return root * root == number;
    }

    public static void main(String[] args) {
        long number = new Scanner(System.in).nextLong();
        System.out.println(isPerfectSquare(number));
    }
}