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2021/12/12に公開

# A - Water Pressure

0.01倍

``````a = int(input())
print(a / 100)
``````

# B - Election

リストに入れて出現回数をカウント。最大カウントの値を返す。

``````import collections

n = int(input())

n_list = []
for i in range(n):
x = input()
n_list.append(x)

c = collections.Counter(n_list)
a = c.most_common()[0]
print(a[0])
``````

# C - Counting 2

``````import bisect

n, q = map(int, input().split())
a_list = list(map(int, input().split()))

q_list = []
for i in range(q):
input_q = int(input())
q_list.append(input_q)

a_sorted = sorted(a_list)

for value in q_list:
ans = bisect.bisect_left(a_sorted, value)
print(len(a_sorted) - ans)
``````

# D - Neighbors

3回以上登場しない かつ 連結グラフにしたときに閉路を持たない(ループを持たない)条件を探す。閉路を求める場合はUnionFIndを使う。

``````from collections import defaultdict

class UnionFind:
def __init__(self, n):
self.n = n
self.parents = [-1] * n

def find(self, x):
if self.parents[x] < 0:
return x
else:
self.parents[x] = self.find(self.parents[x])
return self.parents[x]

def union(self, x, y):
x = self.find(x)
y = self.find(y)

if x == y:
return

if self.parents[x] > self.parents[y]:
x, y = y, x

self.parents[x] += self.parents[y]
self.parents[y] = x

def size(self, x):
return -self.parents[self.find(x)]

def same(self, x, y):
return self.find(x) == self.find(y)

def members(self, x):
root = self.find(x)
return [i for i in range(self.n) if self.find(i) == root]

def roots(self):
return [i for i, x in enumerate(self.parents) if x < 0]

def group_count(self):
return len(self.roots())

def all_group_members(self):
group_members = defaultdict(list)
for member in range(self.n):
group_members[self.find(member)].append(member)
return group_members

def __str__(self):
return "\n".join(f"{r}: {m}" for r, m in self.all_group_members().items())

n, m = map(int, input().split())

if m == 0:
print("Yes")
exit()

uf = UnionFind(n)
cnt = [0] * n

for i in range(m):
u, v = map(int, input().split())
u -= 1
v -= 1
if uf.same(u, v):
print("No")
exit()
uf.union(u, v)
cnt[u] += 1
cnt[v] += 1
if cnt[u] > 2 or cnt[v] > 2:
print("No")
exit()
print("Yes")
``````