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
很简单的一题，估计是AC率最高的一题了吧。
class Solution {
public boolean judgeCircle(String moves) {
if(moves==null||moves.length()==0)
return false;
int upCount = 0 ;
int rightCount = 0 ;
for(int i = 0 ;i<moves.length();i++)
{
char ch = moves.charAt(i);
switch(ch)
{
case('U'): upCount++;
break;
case('D'):
upCount--;
break;
case('R'):
rightCount++;
break;
case('L'):
rightCount--;
break;
default:
break;
}
}
return upCount==0&&rightCount==0;
}
}
