From 4e3f85beac9a8073e4e1e26f80c76c3d3f9c8c46 Mon Sep 17 00:00:00 2001
From: tom4649 <tkaaynakiyoshi@gmail.com>
Date: Thu, 2 Jul 2026 20:39:43 +0900
Subject: [PATCH 1/2] step1,2,3

---
 0090.Subsets-II/memo.md                    | 28 ++++++++++++++++++++++
 0090.Subsets-II/step1_recursion.py         | 17 +++++++++++++
 0090.Subsets-II/step1_recursion_revised.py | 16 +++++++++++++
 0090.Subsets-II/step1_subset.py            | 16 +++++++++++++
 0090.Subsets-II/step1_subset_revised.py    |  9 +++++++
 0090.Subsets-II/step2_backtrack.py         | 22 +++++++++++++++++
 0090.Subsets-II/step3.py                   | 23 ++++++++++++++++++
 7 files changed, 131 insertions(+)
 create mode 100644 0090.Subsets-II/memo.md
 create mode 100644 0090.Subsets-II/step1_recursion.py
 create mode 100644 0090.Subsets-II/step1_recursion_revised.py
 create mode 100644 0090.Subsets-II/step1_subset.py
 create mode 100644 0090.Subsets-II/step1_subset_revised.py
 create mode 100644 0090.Subsets-II/step2_backtrack.py
 create mode 100644 0090.Subsets-II/step3.py

diff --git a/0090.Subsets-II/memo.md b/0090.Subsets-II/memo.md
new file mode 100644
index 0000000..5e82671
--- /dev/null
+++ b/0090.Subsets-II/memo.md
@@ -0,0 +1,28 @@
+# 90. Subsets II
+
+## step1
+Arai 60の問題を覚えていたので、その応用で解けた。12mほど。
+
+時間、空間 O(n)
+
+Arai60の問題: https://leetcode.com/problems/subsets/
+
+もう少し簡潔にもできる
+
+~~ バックトラック ~~ 再帰 でも解く
+
+subsets[:] とすれば extention という変数を用意しなくてもかける
+
+## 他の人のコード
+https://leetcode.com/problems/subsets-ii/solutions/6877292/video-sorting-the-input-array-to-remove-wzqim/
+
+バックトラックはこの方法だ
+
+再帰をバックトラックで書いたつもりになっていた
+
+## step2
+バックトラック
+subsets.append(subset)として間違えた
+
+## step3
+バックトラック
diff --git a/0090.Subsets-II/step1_recursion.py b/0090.Subsets-II/step1_recursion.py
new file mode 100644
index 0000000..bd6daba
--- /dev/null
+++ b/0090.Subsets-II/step1_recursion.py
@@ -0,0 +1,17 @@
+import collections
+
+class Solution:
+    def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
+        def update_subsets(subsets, num, count):
+            extention = [subset + [num] * i for i in range(1, count+1) for subset in subsets]
+            subsets.extend(extention)
+
+
+        num_to_count = collections.Counter(nums)
+        subsets = [[]]
+        for num, count in num_to_count.items():
+            update_subsets(subsets, num, count)
+
+        return subsets
+
+
diff --git a/0090.Subsets-II/step1_recursion_revised.py b/0090.Subsets-II/step1_recursion_revised.py
new file mode 100644
index 0000000..d597247
--- /dev/null
+++ b/0090.Subsets-II/step1_recursion_revised.py
@@ -0,0 +1,16 @@
+import collections
+
+class Solution:
+    def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
+        def update_subsets(subsets, num, count):
+            subsets.extend([subset + [num] * i for i in range(1, count+1) for subset in subsets[:]])
+
+
+        num_to_count = collections.Counter(nums)
+        subsets = [[]]
+        for num, count in num_to_count.items():
+            update_subsets(subsets, num, count)
+
+        return subsets
+
+
diff --git a/0090.Subsets-II/step1_subset.py b/0090.Subsets-II/step1_subset.py
new file mode 100644
index 0000000..9dc919d
--- /dev/null
+++ b/0090.Subsets-II/step1_subset.py
@@ -0,0 +1,16 @@
+import collections
+
+class Solution:
+    def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
+        num_to_count = collections.defaultdict(int)
+        for n in nums:
+            num_to_count[n] += 1
+
+        subsets = [[]]
+        for n, count in num_to_count.items():
+            extention = []
+            for i in range(1, count+1):
+                extention.extend([subset + [n] * i for subset in subsets])
+            subsets.extend(extention)
+
+        return subsets
diff --git a/0090.Subsets-II/step1_subset_revised.py b/0090.Subsets-II/step1_subset_revised.py
new file mode 100644
index 0000000..c85601b
--- /dev/null
+++ b/0090.Subsets-II/step1_subset_revised.py
@@ -0,0 +1,9 @@
+import collections
+
+class Solution:
+    def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
+        num_to_count = collections.Counter(nums)
+        subsets = [[]]
+        for n, count in num_to_count.items():
+            subsets.extend([subset + [n] * i for i in range(1, count+1) for subset in subsets])
+        return subsets
diff --git a/0090.Subsets-II/step2_backtrack.py b/0090.Subsets-II/step2_backtrack.py
new file mode 100644
index 0000000..0d52255
--- /dev/null
+++ b/0090.Subsets-II/step2_backtrack.py
@@ -0,0 +1,22 @@
+class Solution:
+    def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
+        nums.sort()
+
+        def update_subsets(subsets, i, subset):
+            if i == len(nums):
+                subsets.append(subset[:])
+                return
+
+            subset.append(nums[i])
+            update_subsets(subsets, i+1, subset)
+            subset.pop()
+            while i + 1 < len(nums) and nums[i] == nums[i+1]:
+                i += 1
+            update_subsets(subsets, i+1, subset)
+
+        subsets = []
+        update_subsets(subsets, 0, [])
+
+        return subsets
+
+
diff --git a/0090.Subsets-II/step3.py b/0090.Subsets-II/step3.py
new file mode 100644
index 0000000..0ca92be
--- /dev/null
+++ b/0090.Subsets-II/step3.py
@@ -0,0 +1,23 @@
+class Solution:
+    def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
+        nums.sort()
+        subsets = []
+
+        subset = []
+        def update_subsets(i):
+            if i == len(nums):
+                subsets.append(subset[:])
+                return
+
+            subset.append(nums[i])
+            update_subsets(i+1)
+            subset.pop()
+            while i + 1 < len(nums) and nums[i] == nums[i+1]:
+                i += 1
+            update_subsets(i+1)
+
+        update_subsets(0)
+
+        return subsets
+
+

From cf961301b8c35a9de482e6824a97f4d067f1d0e3 Mon Sep 17 00:00:00 2001
From: tom4649 <tkaaynakiyoshi@gmail.com>
Date: Sat, 4 Jul 2026 07:48:51 +0900
Subject: [PATCH 2/2] Add suggested changes

---
 0090.Subsets-II/step1_recursion.py         | 2 +-
 0090.Subsets-II/step1_recursion_revised.py | 2 +-
 0090.Subsets-II/step1_subset.py            | 2 +-
 0090.Subsets-II/step1_subset_revised.py    | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/0090.Subsets-II/step1_recursion.py b/0090.Subsets-II/step1_recursion.py
index bd6daba..479d5d5 100644
--- a/0090.Subsets-II/step1_recursion.py
+++ b/0090.Subsets-II/step1_recursion.py
@@ -3,7 +3,7 @@
 class Solution:
     def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
         def update_subsets(subsets, num, count):
-            extention = [subset + [num] * i for i in range(1, count+1) for subset in subsets]
+            extention = [subset + [num] * i for i in range(1, count + 1) for subset in subsets]
             subsets.extend(extention)
 
 
diff --git a/0090.Subsets-II/step1_recursion_revised.py b/0090.Subsets-II/step1_recursion_revised.py
index d597247..1c37af2 100644
--- a/0090.Subsets-II/step1_recursion_revised.py
+++ b/0090.Subsets-II/step1_recursion_revised.py
@@ -3,7 +3,7 @@
 class Solution:
     def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
         def update_subsets(subsets, num, count):
-            subsets.extend([subset + [num] * i for i in range(1, count+1) for subset in subsets[:]])
+            subsets.extend([subset + [num] * i for i in range(1, count + 1) for subset in subsets[:]])
 
 
         num_to_count = collections.Counter(nums)
diff --git a/0090.Subsets-II/step1_subset.py b/0090.Subsets-II/step1_subset.py
index 9dc919d..b015e64 100644
--- a/0090.Subsets-II/step1_subset.py
+++ b/0090.Subsets-II/step1_subset.py
@@ -9,7 +9,7 @@ def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
         subsets = [[]]
         for n, count in num_to_count.items():
             extention = []
-            for i in range(1, count+1):
+            for i in range(1, count + 1):
                 extention.extend([subset + [n] * i for subset in subsets])
             subsets.extend(extention)
 
diff --git a/0090.Subsets-II/step1_subset_revised.py b/0090.Subsets-II/step1_subset_revised.py
index c85601b..fce7884 100644
--- a/0090.Subsets-II/step1_subset_revised.py
+++ b/0090.Subsets-II/step1_subset_revised.py
@@ -5,5 +5,5 @@ def subsetsWithDup(self, nums: list[int]) -> list[list[int]]:
         num_to_count = collections.Counter(nums)
         subsets = [[]]
         for n, count in num_to_count.items():
-            subsets.extend([subset + [n] * i for i in range(1, count+1) for subset in subsets])
+            subsets.extend([subset + [n] * i for i in range(1, count + 1) for subset in subsets])
         return subsets