注意int的乘法 65536*65536

import java.util.Set;
import java.util.HashSet;

class Point {
    int x;
    int y;

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

    }
}



    // @Override
    // public boolean equals(Object obj) {
    // if (obj == null) {
    // return false;
    // }
    // MyPoint myPoint = (MyPoint) obj;
    // if (this.x == myPoint.x && this.y == myPoint.y) {
    // return true;
    // } else {
    // return false;
    // }
    // }

    // @Override
    // public int hashCode() {
    // return this.x+this.y;
    // }


class Line {

    public Set<Point> linePoints = new HashSet<Point>();

    public Point A;

    public Point B;

    public Line(Point A, Point B) {
        this.A = A;
        this.B = B;
        linePoints.add(A);
        linePoints.add(B);
    }

    public boolean isOneLine(int x, int y) {
        long V1x = A.x - B.x;
        long V1y = A.y - B.y;

        long V2x = A.x - x;
        long V2y = A.y - y;

        long V3x = B.x - x;
        long V3y = B.y - y;

        long Z12 = V1x * V2y - V1y * V2x;//---------------

        long Z13 = V1x * V3y - V1y * V3x;

        long Z23 = V2x * V3y - V2y * V3x;

        if (Z12 == 0 && Z13 == 0 && Z23 == 0) {

            return true;

        } else {
            return false;
        }
    }

}

public class Solution {

    private Line[] lines = null;

    public int maxPoints(Point[] points) {
        if (points.length == 0) {
            return 0;
        }
        if (points.length == 1) {
            return 1;
        }

        lines = new Line[points.length * points.length];

        for (int i = 0; i < points.length; i++) {
            for (int j = i + 1; j < points.length; j++) {
                if(points[i].x!=points[j].x||points[i].y!=points[j].y)
                {
                    lines[i * points.length + j] = new Line(points[i],points[j]);

                }

            }
        }
        for (int i = 0; i < lines.length; i++) {

            for (int j = 0; j < points.length; j++) {

                if (lines[i] != null && lines[i].isOneLine(points[j].x, points[j].y)) {

                    lines[i].linePoints.add(points[j]);

                }
            }
        }

        int max = 0;
        boolean flag=true;
        for (int i = 0; i < lines.length; i++) {
            if (lines[i] != null && max < lines[i].linePoints.size()) {
                flag=false;
                max = lines[i].linePoints.size();

            }
        }

        if(flag)
        {
            return points.length;
        }

        return max;

    }

    public static void main(String[] args) {
        // System.out.println("xxx");
        Solution sol = new Solution();
        Point[] points = new Point[9];
        //[[84,250],[0,0],[1,0],[0,-70],[0,-70],[1,-1],[21,10],[42,90],[-42,-230]]
        points[0] = new Point(84, 250);
        points[1] = new Point(0,0);
        points[2] = new Point(1, 0);
        points[3] = new Point(0, -70);
        points[4] = new Point(0, -70);
        points[5] = new Point(1, -1);
        points[6] = new Point(21, 10);
        points[7] = new Point(42, 90);
        points[8] = new Point(-42, -230);

        int max = sol.maxPoints(points);
        System.out.println(max);
        for (int i = 0; i < sol.lines.length; i++) {
            if (sol.lines[i] != null) {
                for (Point point : sol.lines[i].linePoints) {
                    System.out.println("(" + point.x + "," + point.y + ")");
                }
                System.out.println();
            }

        }

        // Set<MyPoint> myPoints=new HashSet<MyPoint>();
        // myPoints.add(new MyPoint(new Point(0,0)));
        // myPoints.add(new MyPoint(new Point(0,0)));
        // myPoints.add(new MyPoint(new Point(0,0)));
        // System.out.println(myPoints.size());

    }
}