正方形个数

import java.util.*; public class Main { public static void main(String[] args){ Scanner in = new Scanner(System.in); while(in.hasNextInt()){ int n = in.nextInt(); Point[] yp = new Point[n]; for(int i=0; i<n; i++){ yp[i] = new Point(in.nextInt(), in.nextInt()); } Point[] sp = new Point[4]; System.out.println(n<4?0:findRec(yp, sp, 0, 0, 0)); } }

public static int findRec(Point[] yp, Point[] sp, int i, int c, int f){
    if(c == 4) return isRec(sp) + f;
    if(i >= yp.length) return f;
    int wi = findRec(yp, sp, i+1, c, f);
    sp[c] = yp[i];
    int yi = findRec(yp, sp, i+1, c+1, f);
    sp[c] = null;
    return wi+yi;
}

public static int isRec(Point[] p){
    Point[] p1 = new Point[2];
    Point[] p2 = new Point[2];
    p1[0] = p[0];
    for(int i=1; i<p.length; i++){
        p1[1] = p[i];
        int k = 0;
        for(int j=1; j<p.length; j++){
            if(j==i) continue;
            p2[k++] = p[j];
        }
        if((p1[1].x-p1[0].x)*(p2[1].x-p2[0].x)+(p1[1].y-p1[0].y)*(p2[1].y-p2[0].y)==0&&
                (p1[1].x+p1[0].x)==(p2[1].x+p2[0].x)&&
                (p1[1].y+p1[0].y)==(p2[1].y+p2[0].y)&&
                Math.pow(p1[1].x-p1[0].x, 2)+Math.pow(p1[1].y-p1[0].y, 2)==
                Math.pow(p2[1].x-p2[0].x, 2)+Math.pow(p2[1].y-p2[0].y, 2)){
            return 1;
        }
    }
    return 0;
}

public static class Point{
    int x;
    int y;
    Point(int x, int y){
        this.x = x;
        this.y = y;
    }
}

}