1 files changed, 79 insertions, 0 deletions
diff --git a/1_array_hashing/contains_duplicate.py b/1_array_hashing/contains_duplicate.py
new file mode 100644
index 0000000..142bcca
--- /dev/null
+++ b/1_array_hashing/contains_duplicate.py
@@ -0,0 +1,79 @@
+"""
+Question
+
+Duplicate Integer
+
+Easy
+
+Given an integer array nums, return true if any value appears more than once in the array, otherwise return false.
+
+Example 1:
+
+Input: nums = [1, 2, 3, 3]
+
+Output: true
+
+Example 2:
+
+Input: nums = [1, 2, 3, 4]
+
+Output: false
+"""
+
+
+class Solution:
+    # 1. brute force
+    def brute_force(self, nums: list[int]) -> bool:
+        return False
+
+    # 2. sorting
+    def sorting(self, nums: list[int]) -> bool:
+        return False
+
+    # 3. hashset
+    def hashset(self, nums: list[int]) -> bool:
+        hs = set()
+        for i in range(len(nums)):
+            if nums[i] in hs:
+                return True
+            hs.add(nums[i])
+        return False
+
+
+case1 = [1, 2, 3, 4, 5]
+case2 = [2, 2, 3, 4, 5]
+case3 = [3, 4, 1, 6, 3]
+solution = Solution()
+print(f"hashset case1: {solution.hashset(case1)}")
+print(f"hashset case2: {solution.hashset(case2)}")
+print(f"hashset case3: {solution.hashset(case3)}")
+
+
+"""
+Solution
+
+url: https://neetcode.io/problems/duplicate-integer
+video: https://youtu.be/3OamzN90kPg
+
+1. brute force
+time: O(n^2)
+space: O(1)
+
+2. sort
+time: O(nlogn)
+space: O(1)
+
+3. hashset
+time: O(n)
+space: O(n)
+code:
+class Solution:
+    def hasDuplicate(self, nums: List[int]) -> bool:
+        hashset = set()
+
+        for n in nums:
+            if n in hashset:
+                return True
+            hashset.add(n)
+        return False
+"""