Find 2 numbers in an unsorted array equal to a given sum

Question

We need to find pair of numbers in an array whose sum is equal to a given value.

A = {6,4,5,7,9,1,2}

Sum = 10 Then the pairs are - {6,4} ,

Answer 1

Create a dictionary with pairs Key (number from the list) and the Value is the number which is necessary to obtain a desired value. Next, check the presence of the pairs of numbers in the list.

def check_sum_in_list(p_list, p_check_sum):
    l_dict = {i: (p_check_sum - i) for i in p_list}
    for key, value in l_dict.items():
        if key in p_list and value in p_list:
            return True
    return False


if __name__ == '__main__':
    l1 = [1, 3, 7, 12, 72, 2, 8]
    l2 = [1, 2, 2, 4, 7, 4, 13, 32]

    print(check_sum_in_list(l1, 10))
    print(check_sum_in_list(l2, 99))

Output:
True
Flase

version 2

import random


def check_sum_in_list(p_list, p_searched_sum):
    print(list(p_list))
    l_dict = {i: p_searched_sum - i for i in set(p_list)}
    for key, value in l_dict.items():
        if key in p_list and value in p_list:
            if p_list.index(key) != p_list.index(value):
                print(key, value)
                return True
    return False


if __name__ == '__main__':
    l1 = []
    for i in range(1, 2000000):
        l1.append(random.randrange(1, 1000))

    j = 0
    i = 9
    while i < len(l1):
        if check_sum_in_list(l1[j:i], 100):
            print('Found')
            break
        else:
            print('Continue searching')
            j = i
            i = i + 10

Output:
...
[154, 596, 758, 924, 797, 379, 731, 278, 992, 167]
Continue searching
[808, 730, 216, 15, 261, 149, 65, 386, 670, 770]
Continue searching
[961, 632, 39, 888, 61, 18, 166, 167, 474, 108]
39 61
Finded
[Finished in 3.9s]