From 898c42a990b57ab9824d53efd7a2b647dd2724d9 Mon Sep 17 00:00:00 2001
From: Lozakaka <102352821+Lozakaka@users.noreply.github.com>
Date: Mon, 8 May 2023 18:10:28 -0400
Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9Ejava=E7=94=A8set2k?=
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---
 problems/0491.递增子序列.md | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/problems/0491.递增子序列.md b/problems/0491.递增子序列.md
index 436dbf01..2a58f550 100644
--- a/problems/0491.递增子序列.md
+++ b/problems/0491.递增子序列.md
@@ -203,6 +203,30 @@ public:
 
 
 ### Java 
+```Java
+//using set, aligned with the unimproved method
+class Solution {
+    List<List<Integer>> result = new ArrayList<>();
+    List<Integer> path = new ArrayList<>();
+    public List<List<Integer>> findSubsequences(int[] nums) {
+        backTracking(nums, 0);
+        return result;
+    }
+    private void backTracking(int[] nums, int startIndex){
+        if(path.size() >= 2)
+                result.add(new ArrayList<>(path));            
+        HashSet<Integer> hs = new HashSet<>();
+        for(int i = startIndex; i < nums.length; i++){
+            if(!path.isEmpty() && path.get(path.size() -1 ) > nums[i] || hs.contains(nums[i]))
+                continue;
+            hs.add(nums[i]);
+            path.add(nums[i]);
+            backTracking(nums, i + 1);
+            path.remove(path.size() - 1);
+        }
+    }
+}
+```
 
 ```java
 class Solution {