A. Majority
import sys
def solve():
input = sys.stdin.readline
mod = 10 ** 9 + 7
n = int(input().rstrip('\n'))
s = [str(input().rstrip('\n')) for _ in range(n)]
print("Yes"if s.count("For") > s.count("Against") else "No")
if __name__ == '__main__':
solve()
B. Postal Card
import sys
def solve():
input = sys.stdin.readline
mod = 10 ** 9 + 7
n, m = list(map(int, input().rstrip('\n').split()))
s = [str(input().rstrip('\n'))[-3:] for _ in range(n)]
t = [str(input().rstrip('\n')) for _ in range(m)]
ans = [0] * n
for i in range(n):
for j in range(m):
if s[i] == t[j]:
ans[i] += 1
print(n - ans.count(0))
if __name__ == '__main__':
solve()
C. Path Graph?
import sys
class AlgUnionFind():
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):
return {r: self.members(r) for r in self.roots()}
def __str__(self):
return '\n'.join('{}: {}'.format(r, self.members(r)) for r in self.roots())
def solve():
input = sys.stdin.readline
mod = 10 ** 9 + 7
n, m = list(map(int, input().rstrip('\n').split()))
uf = AlgUnionFind(n)
ls = [0] * n
for i in range(m):
v1, v2 = list(map(int, input().rstrip('\n').split()))
if not uf.same(v1-1, v2-1) and ls[v1-1] <= 1 and ls[v2-1] <= 1:
uf.union(v1-1, v2-1)
ls[v1-1] += 1
ls[v2-1] += 1
else:
print("No")
exit()
print("Yes" if len(uf.roots()) == 1 else "No")
if __name__ == '__main__':
solve()