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:
1.这是一个模拟横纵坐标移动的问题,向左移动x--,向右x++,向上y++,向下y--,最后判断 x == 0 && y == 0即可。
2.直接判断'L','R','U','D'出现的次数是否相等
实现代码:
class Solution {
public:
bool judgeCircle(string moves) {
int x=,y=;
for (int i = ; i < moves.length(); i++){
if (moves[i] == 'L') x--;
else if (moves[i] == 'R') x++;
else if (moves[i] == 'U') y++;
else y--;
}
return x == && y == ;
}
};