O(n) time and O(n) space using Hashtable.

Author: 149ps

1. Two Sum/1. Two Sum.py

@@ -1,8 +1,20 @@
+"""
+Given an array of integers, return indices of the two numbers such that they add up to a specific target.
+
+You may assume that each input would have exactly one solution, and you may not use the same element twice.
+
+Example:
+
+Given nums = [2, 7, 11, 15], target = 9,
+
+Because nums[0] + nums[1] = 2 + 7 = 9,
+return [0, 1].
+"""
 class Solution:
     def twoSum(self, nums: List[int], target: int) -> List[int]:
-        hmap={}
-        for index,val in enumerate(nums):
-            temp = target - val
+        hmap = {}
+        for i,v in enumerate(nums):
+            temp = target - v
             if temp in hmap.keys():
-                return (hmap[temp],index)
-            hmap[val] = index 
+                return [hmap[temp],i]
+            hmap[v] = i