leetcode 657. Judge Route Circle

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

http://www.cnblogs.com/pk28/

嗯，这题我见过，没啥说的，统计一下个数就行

class Solution {
public:
    bool judgeCircle(string moves) {
        int n = moves.size();
        int a = 0, b = 0, c = 0, d = 0;
        for (int i = 0; i < n; ++i) {
            if (moves[i] == 'U') a++;
            if (moves[i] == 'D') b++;
            if (moves[i] == 'L') c++;
            if (moves[i] == 'R') d++;
        }
        if (a==b && c==d) return true;
        return false;
    }
};