657. Judge Route Circle

题目

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

设置两个变量代表x,y轴坐标,然后对应操作就好。最后查看x,y是否还等于0。

代码

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class Solution {
public:
bool judgeCircle(string moves) {
int x = 0,y=0;
for(auto m:moves) {
switch(m) {
case 'L':x--;break;
case 'R':x++;break;
case 'U':y++;break;
case 'D':y--;break;
}
}
if(x == 0 && y == 0) {
return true;
}
else {
return false;
}
}
};
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