pythonset.py

import time
import random

def solution(A, B):
    for i in range(len(A)):
        if A[i] not in B:
            return A[i]

def solution2(A, B):
    H=set(B)
    for i in range(len(A)):
        if A[i] not in H:
            return A[i] 

L = list(range(0, 100000))
L[-3] = -random.randint(0,100000)
R = list(range(0, 100000))
st=time.time()
solution(L, R)
print("elapsed 1", time.time() - st)
st=time.time()
solution2(L, R)
print("elapsed 2", time.time() - st)