20141026 atcoder sample

kensho.py

a = int(raw_input())
n_snacks = a

n_students = int(raw_input())

while (n_snacks % n_students) != 0:
    n_snacks += 1

print (n_snacks - a)

sum.py

n, X = raw_input().split(' ')
n, X = map(int, [n, X])

a = raw_input().split(' ')
a = map(int, a)

flags = format(X, '0'+str(n)+'b')

sum = 0
for i, flg in enumerate(flags):
    if flg == '1':
        sum += a[len(a)-1-i]

print sum