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leetcode/657.py

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+# 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.
+
+
+# Constraints:
+
+# 1 <= moves.length <= 2 * 10^4
+# moves only contains the characters 'U', 'D', 'L' and 'R'.
+
+
+class Solution:
+    def judgeCircle1(self, moves: str) -> bool:
+        horizontal = 0
+        vertical = 0
+        for move in moves:
+            if move == "U":
+                vertical += 1
+            if move == "D":
+                vertical -= 1
+            if move == "L":
+                horizontal -= 1
+            if move == "R":
+                horizontal += 1
+        return horizontal == 0 and vertical == 0
+
+    def judgeCircle(self, moves: str) -> bool:
+        if moves.count("U")!=moves.count("D"):
+            return False
+        if moves.count("L")!=moves.count("R"):
+            return False
+        return True