josephus.py

# Problem: N soldiers are standing in a circle and
# first person has sword and he kills the 2nd person
# and gives the sword to the third person and so on
# till 99th person kills the 100th person gives the
# sword back to the first person, this goes on till
# only one person survives. Print the survivor.


def josephus(people, step=2):
    if step <= 1:
        print("Enter step value, greater than 1")
    else:
        step -= 1  # translated to zero-based indexing
        kill = step  # kill will hold the index of current person to die
        while len(people) > 1:
            print(people.pop(kill))  # pop method removes the element from the list
            kill = (kill + step) % len(people)
        print(people[0], "is safe")


num = int(input("Enter the number of soldiers:  "))
soldiers = [i for i in range(1, num + 1)]  # generates a list of 1..num
josephus(soldiers)