ProgrammingChallenges/bit_difference.py

#!/usr/bin/env python3

import sys

def bitwise_difference(A):
    l = len(A)
    s = 0
    for i in range(32):
        n1 = 0
        for j in range(l):
            n1 += A[j] & 1
            A[j] = A[j] >> 1
        n0 = l - n1
        s += n1 * n0
    return s


if __name__ == "__main__":
    sys.stdin.readline()
    A = sys.stdin.readline().split()
    for i in range(len(A)):
        A[i] = int(A[i])

    print(bitwise_difference(A))