madaidao的专栏

题目链接：https://codeforces.com/contest/1540/problem/B题目大意： n个节点的树。初始的时候，等概率随机选择一个点标记，接来随机选择一个与标记点相连的未标记点来标记，直到所有的点都被标记。根据点被标记的顺序，生成一个数列。这个数列的逆序对的期望个数为多少个？题解： 我们单独计算每对逆序对出现的概率，也就是对于，a在b之前被标记的概率。 我们可以分别计算出每个点第一个选时，逆序对出现的概率。 ...

题目链接：https://codeforces.com/contest/1523/problem/D题目大意：

题目链接：https://codeforces.com/contest/1526/problem/C2题目大意：从左到右有杯酒，每杯酒有一个健康值，喝掉一杯酒后，人的健康值会加。初始的时候人的健康值为0，在最左边的酒，从左到右往后喝，对于一杯酒可以选择喝和不喝，人的健康值在整个过程不能小于0，求最多可以喝几杯酒？题解：方法1:dp表示前杯酒喝了杯最大的健康值这种方法复杂度个人的解法：贪心若当前酒健康值为-4且能喝，后面有杯健康值为-1，那么显然后面这杯健康值为-1的酒是.

题目链接:https://codeforces.com/contest/1525/problem/D题目大意：个数的0,1序列，a[i]=0或1。1的个数一定不超过n的一半。我们需要把所有的1和某个0配对，一个0只能和一个1配对，若和配对，则会消耗的资源。求所有1完成配对后，总资源消耗最少是多少？题解：个人的解法：首先我们可以想一个朴素的贪心匹配方法：我们从前往后扫描，若当前扫描到的数为1，则与目前扫描过的未匹配过的最近的0匹配；若目前扫描到0，则与目前扫描过的未匹配过的1匹配。我们可以

LCP 33. 蓄水题目链接:https://leetcode-cn.com/problems/o8SXZn/题解：暴力枚举蓄水操作的次数计算最优解即可代码如下：class Solution {public: int storeWater(vector<int>& bucket, vector<int>& vat) { int sum=0; for(int i=0;i<int(vat.size());i

题目链接解题思路首先我们容易想到一个简单的动态规划方法：用dp[t][x][y][s][fx][fy]表示在时间t时，s(0或1)表示临时消除法是否使用，以及永久消除法已经用在点(fx,fy)，点(x,y)能否到达。用递推来计算出所有dp状态的结果。但是，这个方法的时间复杂度位O(Tnm2nm5)，其中5为转移复杂度，最坏情况下约为10^9，复杂度太高。我们来考虑如何优化这个dp表达式，显然时间t,坐标(x,y),状态s都无法优化。我们把优化重点放到永久消除卡上。分类讨论：1，如果我们使用永

题目链接：https://codeforces.com/contest/1389/problem/GG. Directing Edgestime limit per test4 secondsmemory limit per test512 megabytesinputstandard inputoutputstandard outputYou are given an undirected connected graph consisting ofnnverti..

题目链接CoinsTime Limit: 3000MS Memory Limit: 30000KTotal Submissions: 29601 Accepted: 10031DescriptionPeople in Silverland use coins.They have coins of value

题目链接Islands and BridgesTime Limit: 4000MS Memory Limit: 65536KTotal Submissions: 9199 Accepted: 2386DescriptionGiven a map of islands and bridges that con

题目链接C. Mr. Kitayuta, the Treasure Huntertime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputThe Shuseki I

题目链接Multiplication PuzzleTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 6612 Accepted: 4029DescriptionThe multiplication puzzle is played with a ro

题目链接RunningTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 5279 Accepted: 1966DescriptionThe cows are trying to become better athletes, so Bessie

题目链接BracketsTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 3470 Accepted: 1792DescriptionWe give the following inductive definition of a “regular

题目链接Brackets SequenceTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 26254 Accepted: 7394 Special JudgeDescriptionLet us define a regular bracke

题目链接Cheapest PalindromeTime Limit: 2000MS Memory Limit: 65536KTotal Submissions: 6117 Accepted: 2981DescriptionKeeping track of all the cows can be a tricky

题目链接Collect CharsTime Limit: 2 Seconds      Memory Limit: 65536 KB Bob was playing MC and was punished by Alice. Bob was trapped in a maze and there were some characters on some specif

题目链接Fixed PointTime Limit: 2 Seconds      Memory Limit: 65536 KB In mathematics, a fixed point (sometimes shortened to fixpoint, also known as an invariant point) of a function is an e

题目链接不要62Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 21020    Accepted Submission(s): 7180Problem Description杭州人称那些傻乎乎粘嗒嗒的人为6

题目链接LOOPSTime Limit: 15000/5000 MS (Java/Others)    Memory Limit: 125536/65536 K (Java/Others)Total Submission(s): 2726    Accepted Submission(s): 1126Problem DescriptionAkemi Homura i

题目链接String painterTime Limit: 5000/2000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1853    Accepted Submission(s): 820Problem DescriptionThere ar

题目链接FootballTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 3284 Accepted: 1679DescriptionConsider a single-elimination football tournament involv

题意：一个人先后要参加n个舞会，已知他n个舞会要穿什么样的衣服。一件衣服他脱了以后，就不会再穿。他可以穿了一种衣服以后，在外面套另一种衣服，再在外面套另一种衣服........。问他最少要准备多少件衣服？题解：原问题是参加完区间[1,n]的舞会，最少要准备多少件衣服。如果第1个舞会要穿的衣服和第i个舞会要穿的衣服相同，假设我们的策略是让第1个舞会和第i个舞会穿同一件衣服，那么区间[2,i-1]

题目链接Coloring Bracketstime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputOnce Petya read a problem about a bracket

题目链接Food DeliveryTime Limit: 2 Seconds      Memory Limit: 65536 KB When we are focusing on solving problems, we usually prefer to stay in front of computers rather than go out for lunc

题目链接Uvalive 6434 - Number Assignment题意：有N个数

题目 链接吉哥系列故事——恨7不成妻Time Limit: 1000/500 MS (Java/Others)    Memory Limit: 65535/32768 K (Java/Others)Total Submission(s): 1752    Accepted Submission(s): 505Problem Description　　单身!　　

题目链接Greatest Common Increasing SubsequenceTime Limit: 2 Seconds      Memory Limit: 65536 KB      Special Judge You are given two sequences of integer numbers. Write a program to determin

题目链接zhx and contestTime Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)Total Submission(s): 546    Accepted Submission(s): 192Problem DescriptionAs

题意：有一个公式： a1-a2-a3-a4-a5......-anq次修改，每次修改一个位置上的数。            输出每次修改完以后，对于这个式子最多加两个括号后的最大值n题解：每次修改完以后，用动态规划的方法，O(n)的复杂度求最优解。用dp[i][j][k]，表示当前在第i位，还有j个括号没有用，前面有k个有效的前括号的最优值。代码如下：// BE

题目链接最强密码Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 78    Accepted Submission(s): 42Problem Description由于近来密码库被盗的现象层出不穷，度度熊

题目链接E. Gardentime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard outputVasya has a very beautiful country gard

题目链接ArticleTime Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 404    Accepted Submission(s): 119Problem DescriptionAs the term is g

转载自：http://www.cnblogs.com/staginner/archive/2012/03/12/2391925.html          POJ_1160    我们可以用f[i][j]表示建好i个邮局时覆盖到第j个村庄的最优解，那么就可以得到f[i][j]=min{f[i-1][k]+w[k+1][j]}(k    这个题目还可以用四边形不等式去优化，实际上

题目链接F(x)Time Limit: 1000/500 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 2272    Accepted Submission(s): 861Problem DescriptionFor a decimal numbe

题目链接Sightseeing tripTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 5736 Accepted: 2220 Special JudgeDescriptionThere is a travel agency in Adel

题目链接C. Kleofáš and the n-thlontime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputKleofáš is participating in

题目链接题意：N个节点的树，有K个叶子节点，需要将1,2,3...K，K个数任意填入K个叶子节点，每个叶子节点填一个数，每个数只能填入一个叶子节点。每个节点上有个一个运算，运算有两种Max和Min。若运算为Max，则该节点的值等于所有儿子节点的最大值；若运算为Min，该节点的值等于所有儿子节点的最小值。问，根节点可能出现的最大值？题解：关于树的问题，可以考虑树上动态规划的方法。 ...

题目链接1010: [HNOI2008]玩具装箱toyTime Limit: 1 Sec  Memory Limit: 162 MBSubmit: 7027  Solved: 2670[Submit][Status][Discuss]DescriptionP教授要去看奥运，但是他舍不下他的玩具，于是他决定把所有的玩具运到北京。他使用自己的压缩器进行压缩，其可

题目链接DividingTime Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 19596    Accepted Submission(s): 5514Problem DescriptionMarsha and B

题目链接RelocationTime Limit: 1000MS Memory Limit: 65536KTotal Submissions: 2577 Accepted: 1052DescriptionEmma and Eric are moving to their new house they bough