D. Nauuo and Circle •参考资料 [1]:https://www.cnblogs.com/wyxdrqc/p/10990378.html •题意 给出你一个包含 n 个点的树,这 n 个点编号为 1~n: 给出一个圆,圆上放置 n 个位置,第 i 个位置对应树中的某个节点,并且不重复: 求在圆上还原这棵树后,使得边不相交的总方案数: •题解 ①为何每一颗子树一定是连续的一段圆弧? 假设不是连续的圆弧,如图所示: 为了使 x 接到树上,必然会有 x-y 或 x-z 相连的边,这样…

链接:https://codeforces.com/contest/1173/problem/C 题意: Nauuo is a girl who loves playing cards. One day she was playing cards but found that the cards were mixed with some empty ones. There are nn cards numbered from 11 to nn, and they were mixed with…

链接:https://codeforces.com/contest/1173/problem/B 题意: Nauuo is a girl who loves playing chess. One day she invented a game by herself which needs nn chess pieces to play on a m×mm×mchessboard. The rows and columns are numbered from 11 to mm. We denote…

链接:https://codeforces.com/contest/1173/problem/A 题意: Nauuo is a girl who loves writing comments. One day, she posted a comment on Codeforces, wondering whether she would get upvotes or downvotes. It's known that there were xx persons who would upvote…

题目链接: http://codeforces.com/problemset/problem/337/D D. Book of Evil time limit per test2 secondsmemory limit per test256 megabytes 问题描述 Paladin Manao caught the trail of the ancient Book of Evil in a swampy area. This area contains n settlements num…

A - Ostap and Grasshopper zz题能不能跳到  每次只能跳K步 不能跳到# 问能不能T-G  随便跳跳就可以了  第一次居然跳越界0.0  傻子哦  WA1 n,k = map(int,input().split()) s = input() i = 0 st = -1 def jump(st): while(st<n): st+=k if(st>=n or s[st]=='#'): return "NO" if(s[st]=='T' or s[st…

题意:给了一棵树以及每个节点的颜色,1代表黑,0代表白,求将这棵树拆成k棵树,使得每棵树恰好有一个黑色节点的方法数 解法:树形DP问题.定义: dp[u][0]表示以u为根的子树对父亲的贡献为0 dp[u][1]表示以u为根的子树对父亲的贡献为1 现在假设u为白色,它的子树有x,y,z,那么有 dp[u][1]+=dp[x][1]*dp[y][0]*dp[z][0]+dp[x][0]*dp[y][1]*dp[z][0]+dp[x][0]*dp[y][0]*dp[z][1] dp[u][0]+=d…

C. Karen and Supermarket     On the way home, Karen decided to stop by the supermarket to buy some groceries. She needs to buy a lot of goods, but since she is a student her budget is still quite limited. In fact, she can only spend up to b dollars.…

Codeforces Round #564 (Div. 1) A Nauuo and Cards 首先如果牌库中最后的牌是\(1,2,\cdots, k\),那么就模拟一下能不能每次打出第\(k+i\)张牌. 然后考虑每一张牌打出后还要打多少张牌以及这张牌是什么时候入手的,分别记为\(f_i,g_i\),那么答案就是\(f_i+g_i\)的最大值. #include<bits/stdc++.h> #define qmin(x,y) (x=min(x,y)) #define qmax(x,y)…

Codeforces Round #267 (Div. 2) C. George and Job题目链接请点击~ The new ITone 6 has been released recently and George got really keen to buy it. Unfortunately, he didn't have enough money, so George was going to work as a programmer. Now he faced the follow…