Contains Duplicate/ Contains Duplicate II

Author: gavinfish

217 Contains Duplicate.py

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+'''
+Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct.
+'''
+
+class Solution(object):
+    def containsDuplicate(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: bool
+        """
+        return len(nums) != len(set(nums))
+
+
+if __name__ == "__main__":
+    assert Solution().containsDuplicate([1, 2, 3, 4]) == False
+    assert Solution().containsDuplicate([1, 2, 3, 1]) == True

219 Contains Duplicate II.py

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+'''
+Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k.
+'''
+
+class Solution(object):
+    def containsNearbyDuplicate(self, nums, k):
+        """
+        :type nums: List[int]
+        :type k: int
+        :rtype: bool
+        """
+        if not nums:
+            return False
+        m = {}
+        for i in range(len(nums)):
+            if nums[i] in m:
+                if i - m.get(nums[i]) <= k:
+                    return True
+            m[nums[i]] = i
+        return False
+
+
+if __name__ == "__main__":
+    assert Solution().containsNearbyDuplicate([1, 2, 3, 4], 1) == False
+    assert Solution().containsNearbyDuplicate([1, 1, 2, 3], 2) == True
+    assert Solution().containsNearbyDuplicate([1, 2, 3, 1], 2) == False