[每日一题]机器人能否返回原点

样例1:
输入: "UD"
输出: true

样例2:
输入: "LL"
输出: false

public boolean judgeCircle(String moves) {
  // Write your code here
  char[] cs = moves.toCharArray();
  int u = 0;
  int d = 0;
  int l = 0;
  int r = 0;
  for (char c : cs) {
    switch (c) {
      case 'U':
        u++;
        break;
      case 'D':
        d++;
        break;
      case 'R':
        r++;
        break;
      case 'L':
        l++;
        break;
    }
  }
  return u - d == 0 && r - l == 0;
}