LeetCode Judge Route Circle

LeetCode 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

一个机器人,初始站在原点(0,0),UDLR分别表示上下左右,给定一个机器人行走的轨迹字符串,问最终机器人能回到原点吗。

简单题,直接判断走过的水平和垂直方向的差值是否为0,代码如下:

class Solution {
public:
	bool judgeCircle(string moves) {
		int horizon = 0, vertical = 0;
		for (auto c : moves) {
			if (c == 'U')++vertical;
			else if (c == 'D')--vertical;
			else if (c == 'L')--horizon;
			else if (c == 'R')++horizon;
		}
		return horizon == 0 && vertical == 0;
	}
};

本代码提交AC,用时29MS。

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