AtCoder abc142

本期四道水题

C - Go to School
位置数组遍历

D - Disjoint Set of Common Divisors
简单的数论题
求gcd中的质因数个数+1

E - Get Everything
简单dp。会位操作就会做。

# -*- coding: utf-8 -*-
# @time     : 2023/6/2 13:30
# @author   : yhdu@tongwoo.cn
# @desc     :
# @file     : atcoder.py
# @software : PyCharm

import bisect
import copy
import sys
from sortedcontainers import SortedList
from collections import defaultdict, Counter, deque
from functools import lru_cache, cmp_to_key
import heapq
import math
sys.setrecursionlimit(50050)


def main():
    items = sys.version.split()
    if items[0] == '3.10.6':
        fp = open("in.txt")
    else:
        fp = sys.stdin
    n, m = map(int, fp.readline().split())
    a = [0] * m
    c = [0] * m
    for i in range(m):
        t, k = map(int, fp.readline().split())
        a[i] = t
        b = list(map(int, fp.readline().split()))
        for j in range(k):
            c[i] ^= 1 << b[j] - 1

    dp = [[10 ** 18] * (1 << n) for i in range(m + 1)]
    dp[0][0] = 0
    for i in range(m):
        for j in range(1 << n):
            if dp[i][j] >= 10 ** 18:
                continue
            t, val = c[i - 1], a[i - 1]
            dp[i + 1][j | t] = min(dp[i][j] + val, dp[i + 1][j | t])
            dp[i + 1][j] = min(dp[i + 1][j], dp[i][j])
    ans = dp[m][(1 << n) - 1]
    if ans >= 10 ** 18:
        print(-1)
    else:
        print(ans)


if __name__ == "__main__":
    main()

F - Pure
求最小环，简单的bfs就好
什么tarjan的都弱爆了

# -*- coding: utf-8 -*-
# @time     : 2023/6/2 13:30
# @author   : yhdu@tongwoo.cn
# @desc     :
# @file     : atcoder.py
# @software : PyCharm

import bisect
import copy
import sys
from sortedcontainers import SortedList
from collections import defaultdict, Counter, deque
from functools import lru_cache, cmp_to_key
import heapq
import math
sys.setrecursionlimit(50050)


def main():
    items = sys.version.split()
    if items[0] == '3.10.6':
        fp = open("in.txt")
    else:
        fp = sys.stdin
    n, m = map(int, fp.readline().split())
    g = [[] for _ in range(n)]
    for i in range(m):
        a, b = map(int, fp.readline().split())
        a -= 1
        b -= 1
        g[a].append(b)
    dist = [[10 ** 18] * n for i in range(n)]
    pre = [[-1] * n for i in range(n)]

    for i in range(n):
        vis = [0] * n
        qu = deque()
        qu.append(i)
        dist[i][i] = 0
        while qu:
            cur = qu.popleft()
            for v in g[cur]:
                if vis[v] == 0:
                    vis[v] = 1
                    qu.append(v)
                    dist[i][v] = dist[i][cur] + 1
                    pre[i][v] = cur

    ans = 10 ** 18
    sel = -1
    for i in range(n):
        if dist[i][i] != 0:
            if dist[i][i] < ans:
                ans, sel = dist[i][i], i
    if ans == 10 ** 18:
        print(-1)
    else:
        print(ans)
        cur = sel
        for i in range(ans):
            print(cur + 1)
            cur = pre[sel][cur]


if __name__ == "__main__":
    main()