657.机器人能否返回原点 添加python3版本

problems/0657.机器人能否返回原点.md

@@ -91,6 +91,20 @@ class Solution {
 ## Python
 
 ```python
+class Solution:
+    def judgeCircle(self, moves: str) -> bool:
+        x = 0 # 记录当前位置
+        y = 0
+        for i in range(len(moves)):
+            if (moves[i] == 'U'):
+                y += 1
+            if (moves[i] == 'D'):
+                y -= 1
+            if (moves[i] == 'L'):
+                x += 1
+            if (moves[i] == 'R'):
+                x -= 1
+        return x == 0 and y == 0
 ```
 
 ## Go