hashing.py

import random

def find_pairs(M1, M2, val):
    s =list()
    for i in range(0,1000000):
        s.append(M1[i])
    diff = {1000000 -n:n for n in M1}
    pairs = []
    # diff = []
    # for i in range(0,1000000):
    #     diff.append(1000000 - M1[i])
    # print(diff)
    # print(M2[i])
    # pairs = []

    # for i in range(0,1000000):
    #     if(diff[i]==M2[i]):
    #         pairs.append((diff[i], M1[i]))
    for n in M2:
        if n in diff: 
            pairs.append((diff[n], n))
    # print(pairs)
    return pairs


def generate_files(filename,size):
    random.seed()
    with open(filename, 'w') as f:
        for _ in range(size):
            f.write(f"{random.randint(10,1000000)}\n")

def find_pairs_files(fname1, fname2):            
    M1 = []
    M2 = []
    with open(fname1) as f:
        for line in f:
            line = line.strip()
            M1.append(int(line))

    with open(fname2) as f:
        for line in f:
            line = line.strip()
            M2.append(int(line))
    pairs = find_pairs(M1,M2,1000000)
    print(f'Found {len(pairs)} pairs')
    print(len(M1), len(M2))




if __name__ == "__main__":
    find_pairs_files('random1.txt','random2.txt')

$ python3 hashing.py
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
Found 632844 pairs
TIme per pass => 1.3160592321000877