Received via email a message regarding the following HackerRank challenge: https://www.hackerrank.com/challenges/symmetric-difference?utm_campaign=challenge-recommendation&utm_medium=email&utm_source=24-hour-campaign
I liked that a refresher / tutorial preceded the actual challenge.
If interested use the above mentioned link and read the requirements.
Following is a screen capture from the Python console from the Spider 3 IDE:
4 <== M
2 4 5 9
4 <== N
2 4 11 12
5
9
11
12
The first line contains the number of elements in the subsequent line. I did 
not use M to read the four integers. The next line contains the number of elements in the subsequent line. I did not use N to read the next four integers. I used M and N to verify that the program read the proper number of integers.
My code in Python follows:
# -*- coding: utf-8 -*-
import sys
# **** solution ****
M = int(input())
#print(“M:”, M)
# **** input a set of values ****
line = input()
#print(“line:”, line)
# **** split the values into a list ****
l = list(line.split())
#print(“l:”, l)
# **** check the number of elements read ****
if (len(l) != M):
print(“len(l):”, len(l), “!=”, M)
print(“<<< bye bye !!!”)
sys.exit(-1)
# **** ****
l1 = list(map(int, l))
#print(“l1:”, l1)
# **** ****
N = int(input())
#print(“N:”, N)
# **** input a set of values ****
line = input()
#print(“line:”, line)
# **** split the values into a list ****
l = list(line.split())
#print(“l:”, l)
# **** check the number of elements read ****
if (len(l) != N):
print(“len(l):”, len(l), “!=”, N)
print(“<<< bye bye !!!”)
sys.exit(-1)
# **** ****
l2 = list(map(int, l))
#print(“l2:”, l2)
# **** convert lists to sets ****
s1 = set(l1)
#print(“s1:”, s1)
s2 = set(l2)
#print(“s2:”, s2)
# **** get the symetric differences ****
sd = s1.difference(s2)
#print(“sd:”, sd)
dif = set(sd)
#print(“dif:”, dif)
sd = s2.difference(s1)
#print(“sd:”, sd)
dif = dif.union(sd)
#print(“dif:”, dif)
#print(“type(dif):”, type(dif))
# **** convert set to list ****
l = list(dif)
#print(“l:”, l)
# **** sort the list ****
l.sort()
# **** print the sorted list ****
for e in l:
print(e)
# **** reverse the list ****
#l.reverse()
#print(“l:”, l)
The code passed the 10 test cases.
If you have comments or questions regarding this or any other entry in this blog, please do not hesitate and send me a message. Will reply ASAP and will not use your name unless you explicitly allow me to do so.
John
john.canessa@gmail.com
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