61AC - ABC077C: Snuke Festival

ABC091-C (300 points)

import bisect as bi

# input
N = int(input())
A = sorted(list(map(int, input().split())))
B = sorted(list(map(int, input().split())))
C = sorted(list(map(int, input().split())))

count = 0

for b in B:
    i = bi.bisect_left(A, b) # A[0],...,A[i - 1] < b
    k = bi.bisect_right(C, b) # b < C[k],...C[N-1]
    count += i * (N - k)

print(count)