[leetcode-149]Max Points on a Line(java)
来源:互联网 发布:食品 进口商 数据 编辑:程序博客网 时间:2024/05/31 20:52
问题描述:Given n points on a 2D plane, find the maximum number of points that lie on the same straight line.
分析:这道题首先明确,如何确定在同一条直线上?那如果固定一个点,那就是通过某点与该点的向量决定,如果向量一样,那代表同一条直线。但是向量是由(x,y)决定,但是这个值不能用作hashmap的key,所以退而使用斜率。其中斜率要注意x = 0的情况,即将vertical的数单独计算。
同时还有一个问题是重复的问题,之前的思路是如果重复,那就给通过该节点向量中的每个向量的计数+1,但是这样带来了一些问题,当新添加向量时,然后确定计数值。
后来为了简单起见,当出现重复的时候,直接将一个duplicate值更新。然后当处理完所有的节点之后,再对所有的向量值进行一次遍历,然后将value+dulplicate与max比较,并对max更新。
代码如下:324ms
/** * Definition for a point. * class Point { * int x; * int y; * Point() { x = 0; y = 0; } * Point(int a, int b) { x = a; y = b; } * } */public class Solution { public int maxPoints(Point[] points) { int length = points.length; if(length<=2) return length; int max = 2; HashMap<Double,Integer> maps = new HashMap<>(); for(int i = 0;i<length;i++){ maps.clear(); Point now = points[i]; int dulplicate = 1; int vertical = 0; for(int j = i+1;j<length;j++){ Point cmp = points[j]; if(now.x == cmp.x && now.y == cmp.y) dulplicate++; else if(now.x==cmp.x){ vertical++; }else{ double slope = (cmp.y==now.y)?0.0:(1.0)*(cmp.y-now.y)/(cmp.x-now.x); if(maps.containsKey(slope)){ maps.put(slope,maps.get(slope)+1); }else maps.put(slope,1); } } //遍历hashmap Iterator iterator = maps.entrySet().iterator(); while(iterator.hasNext()){ Map.Entry entry = (Map.Entry)iterator.next(); int value = (int)entry.getValue(); if(value+dulplicate>max) max = value+dulplicate; } max = Math.max(vertical+dulplicate,max); } return max; }}
0 0
- [Leetcode] Max Points on a Line (Java)
- LeetCode:Max Points on a Line (Java)
- LeetCode(149)Max Points on a Line
- LeetCode: Max Points on a Line [149]
- LeetCode # 149 Max Points on a Line
- leetcode 149: Max Points on a Line
- Leetcode 149 Max Points on a Line
- LeetCode 149 Max Points on a Line
- [leetcode-149]Max Points on a Line(java)
- [leetcode]149. Max Points on a Line@Java解题报告
- Max Points on a Line | leetcode
- Max Points on a Line LEETCODE
- Leetcode: Max Points on a Line
- LeetCode - Max Points on a Line
- LeetCode 之 Max Points on a Line
- LeetCode | Max Points on a Line
- [LeetCode] Max Points on a Line
- Leetcode: Max Points on a Line
- SQL Server Express MDF 替换问题
- 如何在win7系统下安装IIS
- android 数据存取——SharedPreferences
- Debian 5.0升级GRUB为GRUB2
- C++ 防 陷阱0 宏定义
- [leetcode-149]Max Points on a Line(java)
- Nginx for windows 访问路径包含中文
- Mysql 删除重复的记录
- BackTrack5R3之连网
- memcpy实现
- STEP BY STEP RMAN DUPLICATE Database From RAC ASM To RAC ASM (Doc ID 1913937.1)
- 黑马程序员—JAVA基础学习日记十——反射学习总结
- J版Openstack实现table"更多操作"下拉框
- leetcode GrayCode 递归