Two Sum and the use of Dictionary (Easy) | LeetCode Practice #1
Two Sum Given an array of integers nums and an integer target , return indices of the two numbers such that they add up to target . (You may assume that each input would have exactly one solution, and you may not use the same element twice. You can return the answer in any order.) Python ####Double FOR Loops (Runtime: 2100ms, Memory: 13.3MB) #DECLARE nums: ARRAY of INTEGER #DECLARE target: INTEGER class Solution : def twoSum ( self , nums , target ): Length = len ( nums ) for i in range ( Length - 1 ): for j in range (( i + 1 ), Length ): if nums [ i ] + nums [ j ] == target : return i , j return None ####Hashing Algorithm (Runtime: 0ms, Memory: 12.9MB) #DECLARE nums: ARRAY of INTEGER #DECLARE target: INTEGER class Solution : def twoSum ( self , nums , target ): Seen = {} for i , Value in enumerate ( nums ): if ( target - Value ) in Seen : return Seen [ target - Value ], i Seen [ Value ] = i return None