Add solution #657

Author: JoshCrozier

0657-robot-return-to-origin.js

@@ -0,0 +1,38 @@
+/**
+ * 657. Robot Return to Origin
+ * https://leetcode.com/problems/robot-return-to-origin/
+ * Difficulty: Easy
+ *
+ * There is a robot starting at the position (0, 0), the origin, on a 2D plane. Given a sequence
+ * of its moves, judge if this robot ends up at (0, 0) after it completes its moves.
+ *
+ * You are given a string moves that represents the move sequence of the robot where moves[i]
+ * represents its ith move. Valid moves are 'R' (right), 'L' (left), 'U' (up), and 'D' (down).
+ *
+ * Return true if the robot returns to the origin after it finishes all of its moves, or false
+ * otherwise.
+ *
+ * Note: The way that the robot is "facing" is irrelevant. 'R' will always make the robot move
+ * to the right once, 'L' will always make it move left, etc. Also, assume that the magnitude
+ * of the robot's movement is the same for each move.
+ */
+
+/**
+ * @param {string} moves
+ * @return {boolean}
+ */
+/**
+ * @param {string} moves
+ * @return {boolean}
+ */
+var judgeCircle = function(moves) {
+  let x = 0;
+  let y = 0;
+
+  for (const move of moves) {
+    x += move === 'R' ? 1 : move === 'L' ? -1 : 0;
+    y += move === 'U' ? 1 : move === 'D' ? -1 : 0;
+  }
+
+  return x === 0 && y === 0;
+};

README.md

@@ -494,6 +494,7 @@
 653|[Two Sum IV - Input is a BST](./0653-two-sum-iv-input-is-a-bst.js)|Easy|
 654|[Maximum Binary Tree](./0654-maximum-binary-tree.js)|Medium|
 655|[Print Binary Tree](./0655-print-binary-tree.js)|Medium|
+657|[Robot Return to Origin](./0657-robot-return-to-origin.js)|Easy|
 680|[Valid Palindrome II](./0680-valid-palindrome-ii.js)|Easy|
 684|[Redundant Connection](./0684-redundant-connection.js)|Medium|
 686|[Repeated String Match](./0686-repeated-string-match.js)|Easy|