LeetCode 657. Judge Route Circle

Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the original place.

The move sequence is represented by a string. And each move is represent by a character. The valid robot moves are R (Right), L(Left), U (Up) and D (down). The output should be true or false representing whether the robot makes a circle.

Example 1:

Input: "UD"
Output: true

 

Example 2:

Input: "LL"
Output: false

 

 


题目标签:String

  

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  题目让我们来判定,一个机器人从出发点开始以 “上”, “下”, “左”, “右” 的方式来移动,最后是否回到了原点。
  这一题还是挺容易的,只要把出发点设为x = 0, y = 0 ,然后把每一次的移动 加上1 或者减去1 就可以了。
  具体请看Code。
 
 
 

Java Solution:

Runtime beats 72.84% 

完成日期:03/24/2018

关键词:坐标

关键点:出发点为 x = 0, y = 0

 1 class Solution 
 2 {
 3     public boolean judgeCircle(String moves) 
 4     {
 5         int x = 0;
 6         int y = 0;
 7         
 8         for(char c: moves.toCharArray())
 9         {
10             switch(c)
11             {
12                 case 'R':
13                     x++;
14                     break;
15                 case 'L':
16                     x--;
17                     break;
18                 case 'U':
19                     y++;
20                     break;
21                 case 'D':
22                     y--;
23                     break;
24                 default:
25                     System.out.println("Invalid move");
26             }
27         }
28         
29         
30         return (x == 0 && y == 0);
31     }
32 }

参考资料:n/a

LeetCode 题目列表 - LeetCode Questions List

题目来源:https://leetcode.com/

posted @ 2018-03-25 08:03  Jimmy_Cheng  阅读(141)  评论(0编辑  收藏  举报