Check if 4 points form a Square Java

 PROGRAM TO CHECK IF FOUR POINTS FORM A SQUARE

class MAIN

{

  

// Structure of a point in 2D space

static class Point 

{

    int x, y;

  

        public Point(int x, int y) 

        {

            this.x = x;

            this.y = y;

        }

      

};

  

// A utility function to find square of distance

// from point 'p' to point 'q'

static int distSq(Point p, Point q)

{

    return (p.x - q.x) * (p.x - q.x) + (p.y - q.y) * (p.y - q.y);

}

  

// This function returns true if (p1, p2, p3, p4) form a

// square, otherwise false

static boolean isSquare(Point p1, Point p2, Point p3, Point p4)

{

    int d2 = distSq(p1, p2); // from p1 to p2

    int d3 = distSq(p1, p3); // from p1 to p3

    int d4 = distSq(p1, p4); // from p1 to p4

  

    if (d2 == 0 || d3 == 0 || d4 == 0)    

        return false;

  

    // If lengths if (p1, p2) and (p1, p3) are same, then

    // following conditions must met to form a square.

    // 1) Square of length of (p1, p4) is same as twice

    // the square of (p1, p2)

    // 2) Square of length of (p2, p3) is same

    // as twice the square of (p2, p4)

  

    if (d2 == d3 && 2 * d2 == d4

        && 2 * distSq(p2, p4) == distSq(p2, p3))

    {

        return true;

    }

  

    // The below two cases are similar to above case

    if (d3 == d4 && 2 * d3 == d2

        && 2 * distSq(p3, p2) == distSq(p3, p4)) 

    {

        return true;

    }

    if (d2 == d4 && 2 * d2 == d3

        && 2 * distSq(p2, p3) == distSq(p2, p4))

    {

        return true;

    }

  

    return false;

}

  

// Driver code

public static void main(String[] args)

{

    Point p1 = new Point(20, 10), p2 = new Point( 10, 20 ),

        p3 = new Point(20, 20 ), p4 = new Point( 10, 10 );

    System.out.println(isSquare(p1, p2, p3, p4)==true ? "Yes" : "No");

}

}

OUTPUT

Yes

CREDITS: https://www.geeksforgeeks.org/check-given-four-points-form-square/