Merge pull request doocs#237 from phuclhv/master

Add Solution.py for problem 0219.Contains Duplicate II

Author: yanglbme

solution/0219.Contains Duplicate II/Solution.py

@@ -0,0 +1,32 @@
+'''
+https://leetcode.com/problems/contains-duplicate-ii/
+
+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 absolute difference between i and j is at most k.
+'''
+# Performance
+'''
+Runtime: 96 ms, faster than 93.53% of Python3 online submissions for Contains Duplicate II.
+Memory Usage: 20.5 MB, less than 62.50% of Python3 online submissions for Contains Duplicate II.
+'''
+
+# Algorithm Explained
+'''
+Create a hashmap to remember the most recent position of unique values
+If we found duplicate and the range is less than k, then return true
+Else remember that index
+
+Space: O(n) with n is the number of original array
+Complexity: O(n)
+'''
+class Solution:
+  def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
+    pos = {}
+    for idx, element in enumerate(nums):
+      if element in pos and idx - pos[element] <= k:
+        return True
+      pos[element] = idx
+    return False
+            
+            
+                
+