【Python】AtCoderのA問題を３０問だけ解く（for Python初心者）

速度に拘ったプログラミングが出来るよう、今月末までにA, B, C問題それぞれ30問ずつ解く。
A問題は組み込み関数を知ってるだけで解けてしまうので、難易度的には低いと思います。
とはいえ、基礎を確実に抑えているか否かによって、成長速度は変わってくると感じているので、焦らず解く。

ここでは、問題の詳細は述べず、単にプログラムを張るに留める。

# 注釈
入力の受付に```input().split(" ")```と書いているが、```input().split()```でもイケます。（後半で気がついた。）

# A - Weather Prediction
```python
S = input()

clouds = ["Sunny", "Cloudy", "Rainy"]

if S == "Sunny":
    print("Cloudy")
elif S == "Cloudy":
    print("Rainy")
else:
    print("Sunny")

```

# A - Password

```python
N = int(input())
c = N ** 3
print(c)
```

# A - Tenki
```python
S = list(input())
T = list(input())

i = 0
ans_cnt = 0

while i < len(S):
    if S[i] == T[i]:
        ans_cnt += 1
    i += 1

print(ans_cnt)
```

# A. Red or Not
```python
a = int(input())
s = input()

if a >= 3200:
    print(s)
else:
    print("red")
```

# A. +-x
```python
A, B = list(map(int, input().split(" ")))

result = [A + B, A - B, A * B]
result.sort(reverse=True)
print(result[0])
```

# A. Transfer
```python
A, B, C = map(int, input().split(" "))

if B + C <= A:
    print(0)
else:
    print(C - (A - B))
```

# A - Dodecagon
```python
r = int(input())
print(3 * r ** 2)
```

# A. T or T
```python
N, A, B = map(int, input().split(" "))
print(min(A * N, B))
```

# A. Fifty-Fifty
```python
S = list(input())
S_set = set(S)

for target in S_set:
    if S.count(target) != 2:
        print("No")
        exit()

print("Yes")
```

# A. Security
```python
S = list(input())
i = 0
while i < len(S) - 1:
    if S[i] == S[i+1]:
        print("Bad")
        exit()
    i += 1
print("Good")
```

# A - Rounding
```python
X, A = input().split(" ")

if X < A:
    print(0)
else:
    print(10)
```

# A - Airplane
```python
flight_times = list(map(int, input().split(" ")))
flight_times.sort()
print(flight_times[0] + flight_times[1])
```

# A - Apple Pie
``` python
A, P = map(int, input().split(" "))
print(int((A*3+P) / 2))
```

# A - Ferris Wheel
```python
A, B = list(map(int, input().split(" ")))
if A >= 13:
    print(B)
elif 6 <= A <= B:
    print(int(B/2))
else:
    print(0)
```

# A - Changing a Character
```python
N, K = list(map(int, input().split()))
S = list(input())
S[K-1] = S[K-1].lower()
print("".join(S))
```

# A - Biscuit Generator
```python
A, B, T = map(int, input().split())

cnt = T//A
print(cnt * B)
```

# A. Buttons
```python
A, B = map(int, input().split())
print(max(2*A-1, 2*B-1, A+B))
```

# A - Five Antennas
```python
import itertools

plots = [int(input()) for _ in range(5)]
k = int(input())

combs = itertools.combinations(plots, 2)
for comb in combs:
    if abs(comb[0]-comb[1]) > k:
        print(":(")
        exit()

print("Yay!")
```

# A - Double Helix
```python
base = {"A": "T", "C": "G", "G": "C", "T": "A"}
print(base[input()])
```

# A - White Cells
```python
H, W = map(int, input().split())
h, w = map(int, input().split())

whole = H*W
points_row = h * W
points_column = w * H
duplicates = h * w

print(whole - (points_row + points_column - duplicates))
```

# A - Favorite Sound
```python
A, B, C = map(int, input().split())

if B // A < C:
    print(B // A)
else:
    print(C)
```

# A - Still TBD
```python
from datetime import datetime

S = datetime.strptime(input(), "%Y/%m/%d")
target = datetime(2019, 4, 30)

if S <= target:
    print("Heisei")
else:
    print("TBD")
```

# A - B +/- A
```python
A, B = map(int, input().split())

if B % A == 0:
    print(A + B)
else:
    print(B - A)
```

# A - Entrance Examination
```python

T, X = map(int, input().split())
print(T/X)
```

# A - Right Triangle
```python
AB, BC, CA = map(int, input().split())
print(int(AB * BC / 2))
```

# A - Christmas Eve Eve Eve
```python
days = {"22": "Christmas Eve Eve Eve", "23": "Christmas Eve Eve", "24": "Christmas Eve", "25": "Christmas"}
print(days[input()])
```

# A - 753
```python
accepted = [3, 5, 7]
x = int(input())

if x in accepted:
    print("YES")
else:
    print("NO")
```

# A - Discount Fare
```python
X, Y = map(int, input().split())
print(int(X + Y/2))
```

# A - Programming Education
```python
N = int(input())
if N == 1:
    print("Hello World")
else:
    A, B = [int(input()) for _ in range(2)]
    print(A + B)
```

# A - AtCoder Beginner Contest 999
```python
n = list(input())
result = ""

for num in n:
    if num == "1":
        result += "9"
    else:
        result += "1"

print(result)
```

# A - Maximize the Formula
```python
choices = list(map(int, input().split()))
choices.sort(reverse=True)
print(int(str(choices[0]) + str(choices[1])) + choices[2])
```

愚直に解くならこう

```python
from itertools import permutations
from copy import copy

choices = list(map(int, input().split()))
combs = permutations(choices, 2)

res = 0

for comb in combs:
    left = copy(choices)
    for num in comb:
        left.remove(num)
    right = int(str(comb[0]) + str(comb[1]))
    total = left[0] + right
    if total > res:
        res = total

print(res)
```

# 最後に
最後まで閲覧いただきありがとうございます。
できるだけ短く、簡潔なコードを書いたつもりですが、アドバイス等頂けますと幸いです・・・！
明日はB問題解くよ！