657

idf · idf · commit 49ee4fdede14 · 2019-06-17T23:18:10.000-07:00
diff --git a/657 Robot Return to Origin.py b/657 Robot Return to Origin.py
@@ -0,0 +1,39 @@
+#!/usr/bin/python3
+"""
+There is a robot starting at 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.
+
+The move sequence is represented by a string, and the character moves[i]
+represents its ith move. Valid moves are R (right), L (left), U (up), and D
+(down). If the robot returns to the origin after it finishes all of its moves,
+return true. Otherwise, return false.
+
+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.
+
+Example 1:
+
+Input: "UD"
+Output: true
+Explanation: The robot moves up once, and then down once. All moves have the
+same magnitude, so it ended up at the origin where it started. Therefore, we
+return true.
+
+
+Example 2:
+
+Input: "LL"
+Output: false
+Explanation: The robot moves left twice. It ends up two "moves" to the left of
+the origin. We return false because it is not at the origin at the end of its
+moves.
+"""
+from collections import Counter
+
+
+class Solution:
+    def judgeCircle(self, moves: str) -> bool:
+        counter = Counter(moves)
+        return counter["L"] == counter["R"] and counter["U"] == counter["D"]
