Two Sum

Given an array of integers, return indices of the two numbers such that they add up to a specific target. Cannot use the same element twice.

Problem from LeetCode



In [1]:

    
# Input
# nums = [3,3]
nums = [2,3,5,10,5,10]
target = 10



In [2]:

    
# Method 1
def twoSum(nums, target):
    for i in range(len(nums)):
        for j in range(i+1, len(nums)):    
            if i != j and nums[i] + nums[j] == target:
                return [i, j]
print (twoSum(nums, target))









    



[2, 4]



In [3]:

    
# Method 2
def twoSum(nums, target):
    new_dict = {}
    for i, j in enumerate(nums):
        remain  = target - j
        if remain in new_dict:
            return [new_dict[remain], i]
        else: 
            new_dict[j] = i
print (twoSum(nums, target))









    



[2, 4]