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 boolean judgeCircle(String moves) { if(moves == null || moves.length() == 0) return true; int upOrDown = 0; int leftOrRight = 0; for(int i = 0; i < moves.length(); i++){ switch (moves.charAt(i)){ case ‘U‘: upOrDown ++; break; case ‘D‘: upOrDown --; break; case ‘L‘: leftOrRight --; break; case ‘R‘: leftOrRight ++; break; } } return (upOrDown == 0 && leftOrRight == 0); } }
原文：http://www.cnblogs.com/luckygxf/p/7712106.html