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

思路：

思路比较简单，就是用x记录x方向位置，y记录y方向位置。最后如果还在原点的话说明有circle。

bool judgeCircle(string moves){        int x=0,y=0;    for(auto c:moves)    {      if(c == 'U')y++;      if(c == 'D')y--;      if(c == 'L')x--;      if(c == 'R')x++;    }    if(x==0&&y==0)return true;    return false;    }