LeetCode:657. Judge Route Circle

一：原题

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

二：分析

题目翻译就是机器人经过一系列的移动之后，能否回到原地。

判断方法很简单，题目说了机器人会LRUD四种移动方法，也就是上下左右，那么只需要判断上和下、左和右的次数是否对应相等即可。

换成C++描述的话就是，机器人向上移动时，y++，向下移动时，y--；同理，x++，x--；

最后判断x和y是否为0即可。

三：解答