# input: array of integers
# output: the number that repeats first
# loop through the array
# store the numbers in a hash table
# verify the hash table for repetitions
def findFirstRepetition(array):
#to do: validate the array
data = dict()
for element in array:
if element in data:
return element
else:
data[element]=True
print("Hello World!")
sample1 = [2,5,1,2,3,5,1,2,4]
sample2 = [2,1,1,2,3,5,1,2,4]
sample3 = [2,3,4,5]
result1 = findFirstRepetition(sample1)
result2 = findFirstRepetition(sample2)
result3 = findFirstRepetition(sample3)
assert(result1 == 2)
assert(result2 == 1)
assert(result3 == None)
print("Good bye cruel world")
