From 2119e411b73d818baaec8ca8140c7b619358bd54 Mon Sep 17 00:00:00 2001
From: xsduan98 <xsduan1998@163.com>
Date: Fri, 30 Jul 2021 18:21:18 +0800
Subject: [PATCH] =?UTF-8?q?657.=20=E6=9C=BA=E5=99=A8=E4=BA=BA=E8=83=BD?=
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---
 problems/0657.机器人能否返回原点.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/problems/0657.机器人能否返回原点.md b/problems/0657.机器人能否返回原点.md
index cd26836c..b1fb6f21 100644
--- a/problems/0657.机器人能否返回原点.md
+++ b/problems/0657.机器人能否返回原点.md
@@ -71,6 +71,21 @@ public:
 ## Java
 
 ```java
+// 时间复杂度：O(n)
+// 空间复杂度：如果采用 toCharArray，则是 O（n）;如果使用 charAt，则是 O(1)
+class Solution {
+    public boolean judgeCircle(String moves) {
+        int x = 0;
+        int y = 0;
+        for (char c : moves.toCharArray()) {
+            if (c == 'U') y++;
+            if (c == 'D') y--;
+            if (c == 'L') x++;
+            if (c == 'R') x--;
+        }
+        return x == 0 && y == 0;
+    }
+}
 ```
 
 ## Python