[mandoolala] WEEK 01 solutions

contains-duplicate/mandoolala.py

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+"""
+https://leetcode.com/problems/contains-duplicate/
+"""
+from typing import List
+
+class Solution:
+    def containsDuplicate(self, nums: List[int]) -> bool:
+        '''
+        [Complexity]
+        Time: O(n)
+        Space: O(n)
+        '''
+        return (len(nums) != len(set(nums)))
+
+        '''
+        alternative:
+        nums_set = set()
+        for num in nums:
+            if num in nums_set:
+                return True
+            nums_set.add(num)
+        return False
+        '''

two-sum/mandoolala.py

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+from typing import List
+
+class Solution:
+    def twoSum(self, nums: List[int], target: int) -> List[int]:
+        # return indices of two numbers such that they add up to target
+        '''
+        [Complexity]
+        Time: O(n)
+        Space: O(1)
+        '''
+        nums_dict = {}
+        for idx, num in enumerate(nums):
+            remaining = target - num
+            if remaining in nums_dict:
+                return [idx, nums_dict[remaining]]
+            nums_dict[num] = idx
+        '''
+        [Complexity]
+        Time: O(n^2)
+        Space: O(1)
+
+        for i in range(0,len(nums)-1):
+            for j in range(i+1, len(nums)):
+                sum = nums[i] + nums[j]
+                if sum == target:
+                    return [i, j]
+        '''