Bittilista

#!/usr/bin/env python3

# jono alkaa samalla bitillä kuin päättyy, joten jonossa on
# ensin 2^(n-2) kpl 0..0 -ratkaisuja, sitten saman verran 1..1 -ratkaisuja

def binaariksi(x, pit):
    s = bin(x)[2:]
    etunollat = '0' * (pit - len(s))
    return etunollat + s

def main():
    n, k = [int(x) for x in input().split()]
    nollaratkaisuja = 2 ** (n - 2)
    if k > nollaratkaisuja:
        k -= nollaratkaisuja
        print('1' + binaariksi(k - 1, n - 2) + '1')
    else:
        print('0' + binaariksi(k - 1, n - 2) + '0')

if __name__ == '__main__':
    main()

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 1

Verdict: ACCEPTED

Test 3

Group: 1

Verdict: ACCEPTED

Test 4

Group: 1

Verdict: ACCEPTED

Test 5

Group: 1

Verdict: ACCEPTED

Test 6

Group: 2

Verdict: ACCEPTED

Test 7

Group: 2

Verdict: ACCEPTED

Test 8

Group: 2

Verdict: ACCEPTED

Test 9

Group: 2

Verdict: ACCEPTED

Test 10

Group: 2

Verdict: ACCEPTED

Test 11

Group: 3

Verdict: ACCEPTED

Test 12

Group: 3

Verdict: ACCEPTED

Test 13

Group: 3

Verdict: ACCEPTED

Test 14

Group: 3

Verdict: ACCEPTED

Test 15

Group: 3

Verdict: ACCEPTED