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
class Solution { public: bool judgeCircle(string moves) { int x = 0, y = 0; for (char c : moves) { if (c == ‘U‘) x++; else if (c == ‘D‘) x--; else if (c == ‘L‘) y++; else if (c == ‘R‘) y--; } return !(x || y); } }; // 19 ms
原文：http://www.cnblogs.com/immjc/p/7490397.html