Add solution #1041

Author: JoshCrozier

README.md

@@ -165,6 +165,7 @@
 1009|[Complement of Base 10 Integer](./1009-complement-of-base-10-integer.js)|Easy|
 1010|[Pairs of Songs With Total Durations Divisible by 60](./1010-pairs-of-songs-with-total-durations-divisible-by-60.js)|Medium|
 1037|[Valid Boomerang](./1037-valid-boomerang.js)|Easy|
+1041|[Robot Bounded In Circle](./1041-robot-bounded-in-circle.js)|Medium|
 1103|[Distribute Candies to People](./1103-distribute-candies-to-people.js)|Easy|
 1108|[Defanging an IP Address](./1108-defanging-an-ip-address.js)|Easy|
 1189|[Maximum Number of Balloons](./1189-maximum-number-of-balloons.js)|Easy|

solutions/1041-robot-bounded-in-circle.js

@@ -0,0 +1,34 @@
+/**
+ * 1041. Robot Bounded In Circle
+ * https://leetcode.com/problems/robot-bounded-in-circle/
+ * Difficulty: Medium
+ *
+ * On an infinite plane, a robot initially stands at (0, 0) and faces north.
+ * The robot can receive one of three instructions:
+ * - "G": go straight 1 unit;
+ * - "L": turn 90 degrees to the left;
+ * - "R": turn 90 degrees to the right.
+ *
+ * The robot performs the instructions given in order, and repeats them forever.
+ * Return true if and only if there exists a circle in the plane such that the
+ * robot never leaves the circle.
+ */
+
+/**
+ * @param {string} instructions
+ * @return {boolean}
+ */
+var isRobotBounded = function(instructions) {
+  let x = 0, y = 0;
+  let dx = 0, dy = 1;
+
+  for (const direction of instructions) {
+    switch (direction) {
+      case 'R': [dx, dy] = [dy, -dx]; break;
+      case 'L': [dy, dx] = [dx, -dy]; break;
+      case 'G': [x, y] = [x + dx, y + dy]; break;
+    }
+  }
+
+  return (x === 0 && y === 0) || dy !== 1;
+}