AtCoder Beginners Contest 081 [A to C]

A. Placing Marbles … Count “1” in the input string

print(input().count("1"))

1	print(input().count("1"))

B. Shift Only … Add the result into the temporary list if the number modulo 2 is 0. In each iteration of the list, compare the length of the original list and temporary list.

n = int(input())
a = list(map(int, input().split()))

result = 0

while True:
    temp_a = []
    for num in a:
        if num%2 == 0:
            temp_a.append(num//2)
    if len(temp_a) != n:
        break
    a = temp_a
    result += 1

print(result)

n = int(input())

a = list(map(int, input().split()))

result = 0

while True:

temp_a = []

for num in a:

if num%2 == 0:

temp_a.append(num//2)

if len(temp_a) != n:

break

a = temp_a

result += 1

print(result)

C. Not So Diverse … In python, there is a Counter function which can create a dictionary from a list. In this case, take a list of numbers, and make a dictionary which has “number” as a key, and “times of the number appears in the list” as a value.

n = int(input())
a = list(map(int, input().split()))

result = 0

while True:
    temp_a = []
    for num in a:
        if num%2 == 0:
            temp_a.append(num//2)
    if len(temp_a) != n:
        break
    a = temp_a
    result += 1

print(result)