Josephus http://danvk.org/josephus.html

josephus-readable.py

#!/usr/bin/env python3
import sys
size, every_x, current = [int(x) for x in sys.argv[1:]]
alive, till_kill = [True] * size, 0
while True:
    if alive[current]:
        if sum(alive) == 1:
            break
        elif till_kill == 0:
            alive[current] = False
            till_kill = every_x - 1
        else:
            till_kill -= 1
    current += 1 if current < size - 1 else 1 - size
print("Josephus should be at position {} to survive.".format(current))

josephus-short.py

#!/usr/bin/env python3
import sys
s, k, c = [int(x) for x in sys.argv[1:]]
a, tn = [True] * s, 0
while True:
    if a[c]:
        if sum(a) == 1: break
        elif tn == 0: a[c] = False; tn = k - 1
        else: tn -= 1
    c += 1 if c < s - 1 else 1 - s
print("Josephus should be at position {} to survive.".format(c))