add leetcode solution

Author: MccreeFei

leetcode/src/main/java/cn/mccreefei/technologystack/leetcode/RobotBoundedInCircle.java

@@ -0,0 +1,26 @@
+package cn.mccreefei.technologystack.leetcode;
+
+/**
+ * @author MccreeFei
+ * @create 2020-09-18 下午1:46
+ * @refer <href>https://leetcode.com/problems/robot-bounded-in-circle/</href>
+ * @idea 在一次指令全部走完后 如果机器人在起点或者机器人的前进方向改变 则走的是一个循环
+ */
+public class RobotBoundedInCircle {
+    public boolean isRobotBounded(String instructions) {
+        int d = 0, x = 0, y = 0;
+        int[][] move = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
+        for (int i = 0; i < instructions.length(); i++) {
+            char c = instructions.charAt(i);
+            if (c == 'R') {
+                d = (d  + 1) % 4;
+            } else if (c == 'L') {
+                d = (d + 3) % 4;
+            } else {
+                x += move[d][0];
+                y += move[d][1];
+            }
+        }
+        return (x == 0 && y == 0) || d != 0;
+    }
+}