Create robot-bounded-in-circle.cpp

Author: kamyu104

C++/robot-bounded-in-circle.cpp

@@ -0,0 +1,22 @@
+// Time:  O(n)
+// Space: O(1)
+
+class Solution {
+public:
+    bool isRobotBounded(string instructions) {
+        static const vector<vector<int>>& directions = {{ 1, 0}, {0, -1},
+                                                        {-1, 0}, {0, 1}};
+        int x = 0, y = 0, i = 0;
+        
+        for (const auto& instruction : instructions) {
+            if (instruction == 'R') {
+                i = (i + 1) % 4;
+            } else if (instruction == 'L') {
+                i = (4 + i - 1) % 4;
+            } else {
+                x += directions[i][0], y += directions[i][1];
+            }
+        }
+        return (x == 0 && y == 0) || i > 0;
+    }
+};