349.intersection-of-two-arrays

Author: geemaple

README.md

@@ -27,6 +27,7 @@ This is a **continually updated, open source** project.
 |  Problem          |  Solution       |  Time           | Difficulty    | Tag          | Note| 
 | ----------------- | --------------- | --------------- | ------------- |--------------|-----|
 | 88.merge-sorted-array | [python](./algorithm/88.merge-sorted-array.py) | O(N + M) | Easy |
+| 349.intersection-of-two-arrays | [python](./algorithm/349.intersection-of-two-arrays.py) O(N + M) |Easy
 
 ## Two Pointers
 
@@ -35,7 +36,7 @@ This is a **continually updated, open source** project.
 | 19.remove-nth-node-from-end-of-list | [python](./algorithm/19.remove-nth-node-from-end-of-list.py) | O(N) | Medium
 | 141.linked-list-cycle | [python](./algorithm/141.linked-list-cycle.py) | O(N) | Easy | linked-list
 | 142.linked-list-cycle-ii | [python](./algorithm/142.linked-list-cycle-ii.py) | O(N) | Medium | linked-list
-| 160.intersection-of-two-linked-lists | [python](./algorithm/160.intersection-of-two-linked-lists.py) | O(N+M) | Easy | linked-list
+| 160.intersection-of-two-linked-lists | [python](./algorithm/160.intersection-of-two-linked-lists.py) | O(N + M) | Easy | linked-list
 
 
 ## Linked List

algorithm/349.intersection-of-two-arrays.py

@@ -0,0 +1,16 @@
+class Solution(object):
+    def intersection(self, nums1, nums2):
+        """
+        :type nums1: List[int]
+        :type nums2: List[int]
+        :rtype: List[int]
+        """
+        
+        # 1. use a set to test if exist O(N + M)
+        # 2. use binary search to find if exist O(NlogN) + O(MlogN) = O((N + M) * logN)
+        # 3. sort left and right, and merge it O(NLogN) + O(MlogM) + min(M, N)
+
+        set1 = set(nums1)
+        set2 = set(nums2)
+
+        return list(set1.intersection(set2))