Coloring Trees Problem Description: ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be naughty and color the trees in the park. The trees are numbered with integers from 1 to n fr…

C. Coloring Trees time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be…

题目:https://codeforces.com/problemset/problem/711/C 题意:给你n,m,k,代表n个数的序列,有m种颜色可以涂,0代表未涂颜色,其他代表已经涂好了,连着一段是相同颜色的是一个连通块,求正好有k个连通块的最小花费 思路:首先每个位置有可能有m中颜色,而且要满足k个,我们我们可以推出所有情况 dp[n][m][k] n代表前n个数 m代表当前涂m色 k代表满足k个了 #include<cstdio> #include<cmath> #in…

Hard problem 题目链接: http://codeforces.com/contest/706/problem/C Description Vasiliy is fond of solving different tasks. Today he found one he wasn't able to solve himself, so he asks you to help. Vasiliy is given n strings consisting of lowercase Engl…

C. Coloring Trees 题目连接: http://www.codeforces.com/contest/711/problem/C Description ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be naughty and color the trees in the park. The…

C. Coloring Trees   ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be naughty and color the trees in the park. The trees are numbered with integers from 1 to n from left to right…

题目链接 http://codeforces.com/contest/711/problem/C Description ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be naughty and color the trees in the park. The trees are numbered wit…

题目大意:有n个点,由m种颜料,有些点没有涂色,有些点已经涂色了,告诉你每个点涂m种颜色的价格分别是多少, 让你求将这n个点分成k段最少需要多少钱. 思路:动态规划,我们另dp[ i ][ j ][ k ] 表示到i个点为止,分成j段,最后一段的颜色为k的最少值,然后就能很容易地 写出状态转移方程. #include<bits/stdc++.h> #define ll long long using namespace std; ; const ll inf=0x3f3f3f3f3f3f3f3…

题目:http://codeforces.com/problemset/problem/429/B 第一个人初始位置在(1,1),他必须走到(n,m)只能往下或者往右 第二个人初始位置在(n,1),他必须走到(1,m)只能往上或者往右 每个点都有个权值,要求两个人中间相遇一次且只有一次,相遇的那个点的权值不算,两个人的速度可以不一样,然后求出最大值是多少 思路:他的要求是相遇一次且只有一次,那么画几个图其实就只有两个情况了(这图是借了一位大佬的,[小声bb]) 既然知道了这个图分为了这四个区域,…

题目链接:http://codeforces.com/problemset/problem/455/A A. Boredom time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Alex doesn't like boredom. That's why whenever he gets bored, he comes up with…

C. Reberland Linguistics time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output First-rate specialists graduate from Berland State Institute of Peace and Friendship. You are one of the most talent…

题目链接 大意:给你n个物品和m种优惠方式,让你买k种,问最少多少钱. 思路:考虑dpdpdp,dp[x]dp[x]dp[x]表示买xxx种物品的最少花费,然后遍历mmm种优惠方式就行转移就好了. #include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mp make_pair #define pb push_back using namespace std; LL gcd(…

Interesting drink 题目链接: http://codeforces.com/contest/706/problem/B Description Vasiliy likes to rest after a hard work, so you may often meet him in some bar nearby. As all programmers do, he loves the famous drink "Beecola", which can be bough…

Pythagorean Triples 题目链接: http://codeforces.com/contest/707/problem/C Description Katya studies in a fifth grade. Recently her class studied right triangles and the Pythagorean theorem. It appeared, that there are triples of positive integers such th…

题目链接:Codeforces Round #275 (Div. 2) C - Diverse Permutation 题意:一串排列1~n.求一个序列当中相邻两项差的绝对值的个数(指绝对值不同的个数)为k个.求序列. 思路:1~k+1.构造序列前段,之后直接输出剩下的数.前面的构造能够依据,两项差的绝对值为1~k构造. AC代码: #include <stdio.h> #include <string.h> int ans[200010]; bool vis[100010]; i…

Problem  Codeforces Round #556 (Div. 2) - D. Three Religions Time Limit: 3000 mSec Problem Description Input Output Sample Input 6 8abdabc+ 1 a+ 1 d+ 2 b+ 2 c+ 3 a+ 3 b+ 1 c- 2 Sample Output YESYESYESYESYESYESNOYES 题解:动态规划,意识到这个题是动态规划之后难点在于要优化什么东西,本题…

Codeforces Round #521 (Div. 3)  E. Thematic Contests 题目传送门 题意: 现在有n个题目,每种题目有自己的类型要举办一次考试,考试的原则是每天只有一种题目类型一种题目类型只能出现在一天每天的题目类型不能相同,而且后一天的题目数量必须正好为前一天的两倍,第一天的题目数量是任意的求怎么安排能使题目尽量多.注意:不是天数尽量多 思路: 首先我们知道一件事,题目属于哪种类型并不重要,重要的是每种类型的个数所以我们先统计出所有类型的个数,存进一个数组,而…

Codeforces Round #622 (Div. 2) B. Different Rules 题意: 你在参加一个比赛,最终按两场分赛的排名之和排名,每场分赛中不存在名次并列,给出参赛人数 n 和你两场分赛的排名 x, y,问你最终名次最小和最大可能是多少. 思路: 以8人为例: x + y = 2,最小第一名,最大第一名:               1 2 3 4 5 6 7 8 8 7 6 5 4 3 2 1               x + y = 3,最小第一名,最大第二名.…

题目链接:https://codeforces.com/contest/1105/problem/E 题意:有 n 个事件,op = 1 表示我可以修改昵称,op = 2 表示一个名为 s_i 的朋友查询我当前的名字.一个朋友是高兴的当且仅当他每次查询我的名字都为 s_i,保证每个朋友至少查询一次我的名字,问最多可以有多少个朋友高兴. 题解:在我两次修改昵称之间,若出现不同的朋友,则他们是互斥的,可以在他们之间连一条边,然后求图的最大独立集,而原图的最大独立集等于补图的最大团,所以求补图的最大团…

题目链接:http://codeforces.com/contest/1041/problem/E 题意:给出n - 1对pair,构造一颗树,使得断开其中一条边,树两边的最大值为 a 和 b . 题解:显示最大值出现的次数为n - 1,且i点出现的次数小于等于i.一个数字 i(< n)出现的次数为 i 到 n 的距离,可构造出一条链使得满足条件. #include <bits/stdc++.h> using namespace std; #define ll long long #de…

http://codeforces.com/group/1EzrFFyOc0/contest/711/problem/C https://blog.csdn.net/qq_36368339/article/details/78568585?locationNum=6&fps=1  题解 题意:(真难理解)有n个点,m种颜色,你要给n个点上没有颜色的点染色.每个点i对应染的颜色j有一个颜料消耗,p[i][j]是点i染成j颜色的花费,你必须保证有k段颜色的点,输出最少花费多少颜料. 思路:题意稍微不…

题目链接: http://codeforces.com/problemset/problem/149/D D. Coloring Brackets time limit per test2 secondsmemory limit per test256 megabytes 问题描述 Once Petya read a problem about a bracket sequence. He gave it much thought but didn't find a solution. Toda…

题目链接:https://vjudge.net/problem/CodeForces-149D D. Coloring Brackets time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Once Petya read a problem about a bracket sequence. He gave it much tho…

题目链接:http://codeforces.com/problemset/problem/711/C O(n^4)的复杂度,以为会超时的 思路:dp[i][j][k]表示第i棵数用颜色k涂完后beauty为j #include<bits/stdc++.h> using namespace std; typedef long long ll; const ll inf=1e15; int c[105]; int p[105][105]; ll dp[105][105][105]; int ma…

题目链接:http://codeforces.com/problemset/problem/796/C 题目大意:有n家银行,第一次可以攻击任意一家银行(能量低于自身),跟被攻击银行相邻或者间接相邻(距离<=2)的银行能量+1,除了第一次外,攻击一家银行需要满足以下条件: ①:跟被攻击过后的银行相邻: ②:能量低于攻击者 ③:银行没有被攻击过 题解:可以从题意得知,比如攻击银行i,如果说银行i能量为t,跟银行距离>=2的银行中能量最大的为mx,自身至少所需能量=max(t+1,mx+2),因为…

 E. Maximum Matching 题目链接:https://codeforces.com/contest/1038/problem/E 题意: 给出n个项链,每条项链左边和右边都有一种颜色(范围1~4),然后每条项链都有对应的价值. 现在你可以任意改变项链的位置,也可以交换左右两边的颜色,问怎么做才能得到最大的价值.一条项链得到价值,就要求其左边的颜色和左边的项链右边颜色相等,并且右边的颜色和右边项链左边的颜色相等. 题解: 分析就可以发现这个题就是找一条权值最大的欧拉路径(每条边刚好经…

D. Alternating Current time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Mad scientist Mike has just finished constructing a new device to search for extraterrestrial intelligence! He was in…

题目链接:http://codeforces.com/contest/448/problem/B ---------------------------------------------------------------------------------------------------------------------------------------------------------- 欢迎光临天资小屋:http://user.qzone.qq.com/593830943/ma…

题目链接:http://codeforces.com/problemset/problem/334/C 题目: 题目大意: 给定数字n,要求构建一个数列使得数列的每一个元素的值都是3的次方,数列之和S大于n,且删掉数列中的任意一个元素数列之和都会小于n,最大化这个数列的长度 题解: 我们考虑从小到大枚举k,取最小的k,使得,答案就是$n/3^k+1$ 为什么呢? 我们考虑一个合法的数列,其中最小的元素是A,那么S一定是A的倍数.假设n是A的倍数,又S>n,那么S-A>=n,这样的话去掉A这个数…

题目链接:https://codeforces.com/contest/1420/problem/D 前言 之前写过这场比赛的题解,不过感觉这一题还可以再单独拿出来好好捋一下思路. 题意 给出 $n$ 个闭区间,问 $k$ 个区间共区间共有多少种情况. 题解一 以区间为单位进行考虑,排序+优先队列. 将所有区间以左端点为第一关键字,右端点为第二关键字从小到大排序,优先队列中存储不小于当前区间左端点的之前区间的右端点,每个区间对答案的贡献即 $C_{(pque.size(),\ k - 1)}$…