657. Judge Route Circle－Epoch

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

想法

想成垂直和水平兩個方向，若是 U 垂直 +1、D -1；水平也如法炮製。

code

bool judgeCircle(char* moves) {
int up = 0;
int right = 0;
while (*moves) {
switch (*moves) {
case 'U':
up++;
break;
case 'D':
up--;
break;
case 'L':
right--;
break;
case 'R':
right++;
break;
}
moves++;
}
if (up == 0 && right == 0)
return true;
else
return false;
}