ABC解説

AtCoder Beginner Contest 292

A. CAPS LOCK

import sys


def solve():
    input = sys.stdin.readline
    mod = 10 ** 9 + 7
    print(str(input().rstrip('\n')).upper())


if __name__ == '__main__':
    solve()

B. Yellow and Red Card

import sys


def solve():
    input = sys.stdin.readline
    mod = 10 ** 9 + 7
    n, q = list(map(int, input().rstrip('\n').split()))
    ls = [0] * n
    for i in range(q):
        e, x = list(map(int, input().rstrip('\n').split()))
        if e == 1:
            ls[x-1] += 1
        elif e == 2:
            ls[x-1] += 2
        else:
            print("Yes" if ls[x-1] >= 2 else "No")



if __name__ == '__main__':
    solve()

C. Four Variables

import sys


def solve():
    input = sys.stdin.readline
    mod = 10 ** 9 + 7
    n = int(input().rstrip('\n'))
    ls = [0] * (n + 1)
    for i in range(1, n + 1):
        for j in range(i, n + 1, i):
            ls[j] += 1
    cnt = 0
    for i in range(1, n + 1):
        for j in range(i, n + 1, i):
            cnt += ls[n - j]
    print(cnt)


if __name__ == '__main__':
    solve()

D. Unicyclic Components

import sys
import collections


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)
    v = sorted([list(map(int, input().rstrip('\n').split())) for _ in range(m)])
    d = collections.defaultdict(int)
    for i in range(m):
        lst = d[uf.find(v[i][1] - 1)]
        d[uf.find(v[i][1] - 1)] = 0
        uf.union(v[i][0]-1, v[i][1]-1)
        d[uf.find(v[i][0] - 1)] += lst + 1
    for v in uf.roots():
        if uf.size(v) != d[v]:
            print("No")
            exit()
    print("Yes")


if __name__ == '__main__':
    solve()

-ABC解説