class Rectangle{ class Node{ private int x; private int y; public void setX(int x){ this.x = x; } public void setY(int y){ this.y = y; } public int getX(){ return this.x; } public int getY(){ return this.y; } public boolean isCoordinate(int cx, int cy){ if( this.x==cx && this.y==cy ) return true; else return false; } } private static final int NUM = 20; private static int sum = 0; public static void main(String[] args){ Rectangle main = new Rectangle(); Node[] coordinate = new Node[NUM]; main.initCoordinate(coordinate); main.printCoordinate(coordinate); main.printGraph(coordinate); System.out.println("================================"); main.evaluate(coordinate); System.out.println("The number of Rectangle:"+sum); } private void initCoordinate(Node[] coordinate){ for(int i = 0; i < coordinate.length; i++){ coordinate[i] = new Node(); coordinate[i].setX((int)(Math.random()*10)); coordinate[i].setY((int)(Math.random()*10)); } } private void printCoordinate(Node[] coordinate){ for(int i = 0; i < coordinate.length; i++){ System.out.println("P"+i+":("+coordinate[i].getX()+","+coordinate[i].getY()+")"); } } private boolean isRectangle(Node p1, Node p2, Node p3, Node p4){ int line1 = (p1.getX()-p2.getX())*(p1.getX()-p2.getX()) + (p1.getY()-p2.getY())*(p1.getY()-p2.getY()); int line2 = (p3.getX()-p4.getX())*(p3.getX()-p4.getX()) + (p3.getY()-p4.getY())*(p3.getY()-p4.getY()); //Avoid the same coordinate, line can not be zero if( line1 == line2 && line1!=0 && line2!=0 ){ int line3 = (p1.getX()-p3.getX())*(p1.getX()-p3.getX()) + (p1.getY()-p3.getY())*(p1.getY()-p3.getY()); int line4 = (p2.getX()-p4.getX())*(p2.getX()-p4.getX()) + (p2.getY()-p4.getY())*(p2.getY()-p4.getY()); if( line3 == line4 && line3!=0 && line4!=0 ) { int line5 = (p1.getX()-p4.getX())*(p1.getX()-p4.getX()) + (p1.getY()-p4.getY())*(p1.getY()-p4.getY()); int line6 = (p2.getX()-p3.getX())*(p2.getX()-p3.getX()) + (p2.getY()-p3.getY())*(p2.getY()-p3.getY()); if( line5 == line6 && line5!=0 && line6!=0 ) return true; } } return false; } private int permutate(Node[] coordinate, int[] arrays){ boolean hasRectangle = false; for(int h = 0; h < 4; h++){ for(int i = 0; i < 4; i++){ if(h==i) continue; for(int j = 0; j < 4; j++){ if( h==j || i==j ) continue; for(int k = 0; k < 4; k++){ if( h==k || i==k || j==k ) continue; if(!hasRectangle){ hasRectangle = isRectangle(coordinate[arrays[h]],coordinate[arrays[i]],coordinate[arrays[j]],coordinate[arrays[k]]); } if(hasRectangle) break; } } } } if(hasRectangle){ System.out.print("p"+arrays[0]+",p"+arrays[1]+",p"+arrays[2]+",p"+arrays[3]+" "); System.out.println("is a Rectangle"); printGraph(coordinate,new int[]{arrays[0],arrays[1],arrays[2],arrays[3]}); return 1; }else { return 0; } } private void evaluate(Node[] coordinate){ for(int h = 0; h < NUM-3; h++){ for(int i = h+1; i < NUM-2; i++){ for(int j = i+1; j < NUM-1; j++){ for(int k = j+1; k < NUM; k++){ sum += permutate(coordinate, new int[]{h,i,j,k}); } } } } } private void printGraph(Node[] coordinate){ System.out.println("All coordinate"); for(int j = 9; j >= 0; j--){ System.out.print(j); for(int i = 0; i < 10; i++){ boolean hasPoint = false; for(int k = 0; k < coordinate.length; k++){ hasPoint = coordinate[k].isCoordinate(i,j); if(hasPoint)break; } if(hasPoint) System.out.print("-o-"); else System.out.print("-|-"); } System.out.println(); } System.out.println(" 0 1 2 3 4 5 6 7 8 9"); } private void printGraph(Node[] coordinate,int[] arrays){ for(int j = 9; j >= 0; j--){ System.out.print(j); for(int i = 0; i < 10; i++){ boolean hasPoint = false; boolean markPoint = false; for(int k = 0; k < coordinate.length; k++){ hasPoint = coordinate[k].isCoordinate(i,j); if(hasPoint)break; } for(int k = 0; k < 4; k++){ markPoint = coordinate[arrays[k]].isCoordinate(i,j); if(markPoint)break; } if(markPoint) System.out.print("-#-"); else if(hasPoint) System.out.print("-o-"); else System.out.print("-|-"); } System.out.println(); } System.out.println(" 0 1 2 3 4 5 6 7 8 9"); System.out.println("================================"); } }

Find Rectangle from Coordinates 2018/01/30