From a87537f7246a5d5221a540aeb58da3362314821c Mon Sep 17 00:00:00 2001
From: Hiro Funatsuka <hiro.funatsuka@gmail.com>
Date: Tue, 21 Apr 2026 22:32:43 +0900
Subject: [PATCH] Solve intersection of two arrays

---
 README.md |  2 +-
 step1.md  | 16 ++++++++++++++++
 step2.md  |  9 +++++++++
 step3.md  |  9 +++++++++
 4 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/README.md b/README.md
index b9c1787..99807fb 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # LeetCode
 
-## 問題: 
+## 問題: [349. Intersection of Two Arrays](https://leetcode.com/problems/intersection-of-two-arrays/description/)
 
 ## 前提
 
diff --git a/step1.md b/step1.md
index 656f813..37aaac3 100644
--- a/step1.md
+++ b/step1.md
@@ -1,4 +1,20 @@
 # Step 1
 
+1. nums1から重複を取り除く
+2. nums2でループを回し、整数がnums1にあったらその数をresに追加、nums1から除外
+
 ```python
+class Solution:
+    def intersection(self, nums1: List[int], nums2: List[int]) -> List[int]:
+        res = []
+        nums1_without_duplicates = {num for num in nums1}
+        for num in nums2:
+            if num in nums1_without_duplicates:
+                res.append(num)
+                nums1_without_duplicates.remove(num)
+        return res
+
 ```
+
+時間計算量: O(n)
+空間計算量: O(n)
diff --git a/step2.md b/step2.md
index 6ec3360..d2c7363 100644
--- a/step2.md
+++ b/step2.md
@@ -1,4 +1,13 @@
 # Step 2
 
 ```python
+class Solution:
+    def intersection(self, nums1: List[int], nums2: List[int]) -> List[int]:
+        res = []
+        nums1_without_duplicates = set(nums1)
+        for num in nums2:
+            if num in nums1_without_duplicates:
+                res.append(num)
+                nums1_without_duplicates.remove(num)
+        return res
 ```
diff --git a/step3.md b/step3.md
index fc9cd1b..2fa271f 100644
--- a/step3.md
+++ b/step3.md
@@ -1,4 +1,13 @@
 # Step 3
 
 ```python
+class Solution:
+    def intersection(self, nums1: List[int], nums2: List[int]) -> List[int]:
+        res = []
+        nums1_without_duplicates = set(nums1)
+        for num in nums2:
+            if num in nums1_without_duplicates:
+                res.append(num)
+                nums1_without_duplicates.remove(num)
+        return res
 ```