leetcode--001 max point on a line

 1 package leetcode;
 2 
 3 import java.util.HashMap;
 4 
 5 class Point{
 6     int x;
 7     int y;
 8     Point(){
 9         x=0;
10         y=0;
11     }
12     Point(int a,int b){
13         x=a;
14         y=b;
15     }
16 }
17 
18 public class MaxPointOnALine {
19     public static int maxPoints(Point[] points) {
20         
21         if(points.length<=2) {
22             return points.length;
23         }
24         //斜率
25         double k = 0.0;
26         int maxPointNum      = 0;
27         int parallelNum =0;
28         int tempMaxPointNum  = 0;
29         int sameNum=0;
30         HashMap map=new HashMap<Double,Integer>();
31         for(int i=0;i<points.length;i++){
32             sameNum=1;
33             parallelNum=0;
34             tempMaxPointNum=0;
35             map.clear();
36             for(int j=i+1;j<points.length;j++){
37                 if(points[i].x==points[j].x&&points[i].y==points[j].y){
38                     sameNum++;
39                 }
40                 else if(points[i].x==points[j].x){
41                     parallelNum++;
42                     
43                 }else {
44                     if(points[i].y==points[j].y){
45                         k=0.0;
46                         
47                     }else{
48                         k=((double)(points[i].y-points[j].y))/(points[i].x-points[j].x);
49                     }
50                     if(map.get(k)==null){
51                         map.put(k, new Integer(1));
52                         if(1>tempMaxPointNum){
53                             tempMaxPointNum=1;
54                         }
55                     }else{
56                         int number=(int)map.get(k);
57                         number++;
58                         map.put(k, number);
59                         if(number>tempMaxPointNum){
60                             tempMaxPointNum=number;
61                         }
62                     }
63                 }
64             }
65             if(parallelNum>1){
66                 if(parallelNum>tempMaxPointNum)
67                     tempMaxPointNum=parallelNum;
68             }
69             tempMaxPointNum+=sameNum;
70             if(tempMaxPointNum>maxPointNum)
71                 maxPointNum=tempMaxPointNum;
72         }
73         return maxPointNum;
74     }
75     public static void main(String[] args){
76         Point[] parr = {new Point(1,1),new Point(1,2)};
77         //maxPoints(parr);
78         System.out.println(maxPoints(parr));
79     }
80 }