From 46ceb72cd01b08f6a734ca87d329c56ec51a51e6 Mon Sep 17 00:00:00 2001
From: erdengk <15596570256@163.com>
Date: Sun, 2 Jan 2022 11:21:56 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=200090.=E5=AD=90=E9=9B=86II.?=
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---
 problems/0090.子集II.md | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/problems/0090.子集II.md b/problems/0090.子集II.md
index 5b92517a..a1e86464 100644
--- a/problems/0090.子集II.md
+++ b/problems/0090.子集II.md
@@ -166,7 +166,7 @@ if (i > startIndex && nums[i] == nums[i - 1] ) {
 
 
 ### Java  
-
+使用used数组
 ```java
 class Solution {
    List<List<Integer>> result = new ArrayList<>();// 存放符合条件结果的集合
@@ -202,6 +202,37 @@ class Solution {
 }
 ```
 
+不使用used数组
+```java
+class Solution {
+
+  List<List<Integer>> res = new ArrayList<>();
+  LinkedList<Integer> path = new LinkedList<>();
+  
+  public List<List<Integer>> subsetsWithDup( int[] nums ) {
+    Arrays.sort( nums );
+    subsetsWithDupHelper( nums, 0 );
+    return res;
+  }
+
+
+  private void subsetsWithDupHelper( int[] nums, int start ) {
+    res.add( new ArrayList<>( path ) );
+
+    for ( int i = start; i < nums.length; i++ ) {
+        // 跳过当前树层使用过的、相同的元素
+      if ( i > start && nums[i - 1] == nums[i] ) {
+        continue;
+      }
+      path.add( nums[i] );
+      subsetsWithDupHelper( nums, i + 1 );
+      path.removeLast();
+    }
+  }
+
+}
+```
+
 ### Python 
 ```python
 class Solution: