'''Solution to Exercise 2.12:
Input:
y = [y1, ..., yN], a list of positive integer numbers
Example:
y = [1, 3, 4, 2] or y = [3, 2, 3, 1, 4, 1]
You can also experiment with random.shuffle from the random library
Typical call of programme:
from python02_ex12a import bijective
y = [1, 3, 4, 2]
print(bijective(y))
'''
def bijective(y):
z = list(range(1,len(y)+1)) # list with numbers from 1 to len(y)
s = sorted(y)
if z == s:
return 'Bingo - bijective!'
else:
return 'Njet - not bijective!'