题目链接 以前做过类似的,USACO,2.3,开始数组开小了,导致数据乱了,然后超数据范围了,.. #include <cstdio> #include <iostream> #include <cmath> using namespace std; #define LL __int64 LL dp[][][]; LL c[][]; int main() { int i,j,n,k,u,h; ; i <= ; i ++) { c[i][] = ; } ; i &l…

Codeforces 9D How many trees? LINK 题目大意就是给你一个n和一个h 问你有多少个n个节点高度不小于h的二叉树 n和h的范围都很小 感觉有无限可能 考虑一下一个很显然的DP dpn,h表示n个节点组成的高度为h的树的方案数dp_{n,h}表示n个节点组成的高度为h的树的方案数dpn,h​表示n个节点组成的高度为h的树的方案数 然后考虑咋转移 首先我们可以肆无忌惮地,枚举一下,因为左右子树的高度至少有一个是h-1,所以我们需要枚举一个子树的大小和另一个子树的高,但是…

CF 983B XOR-pyramid(区间dp,异或) 若有一个长度为m的数组b,定义函数f为: \(f(b) = \begin{cases} b[1] & \quad \text{if } m = 1, \\ f(b[1] \oplus b[2],b[2] \oplus b[3],\dots,b[m-1] \oplus b[m]) & \quad \text{otherwise} \end{cases}\) 现在给出长度为n(n<=5000)的数组a,询问q(q<=1000…

https://codeforces.com/problemset/problem/9/D 一开始居然还想直接找公式的,想了想还是放弃了.原来这种结构是要动态规划. 状态是知道怎么设了,$t_{nh}$ 表示节点数为n个,树高为h的BST的个数. 为什么要这么设状态呢?是考虑到题目关心BST的高度,而且BST具有递归性. 但是这个关键就是要加上n个节点的标记,因为不同节点数量明显可以构造出的高为h的树不同,而且也会影响BST另一侧的构造. 所以说设对状态就做对了一半. 思路就是按高为h的BST是…

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:C. Coloring Trees 题意:给出n棵树的颜色,有些树被染了,有些没有.现在让你把没被染色的树染色.使得beauty = k.问,最少使用的颜料是多少.   K:连续的颜色为一组,一共有多少组. 颜料用量:p[i][j]表示第i棵树用颜料j染色 需要p[i][j]颜料. 思路:DP. dp方程:dp[i][j][k] = a 表示前i棵树beauty = j,且第j棵树染色为k时,需要的最少颜料为a. 状态转移:初始化第一棵树dp[1][1][col[1]or(1~m)].…

传送门:http://codeforces.com/problemset/problem/711/C 题目: 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 wal…

题目链接: 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…

Trees  Accepts: 156  Submissions: 533  Time Limit: 2000/1000 MS (Java/Others)  Memory Limit: 65536/65536 K (Java/Others) Problem Description Today CodeFamer is going to cut trees.There are N trees standing in a line. They are numbered from 1 to N. Th…

D. How many trees? time limit per test 1 second memory limit per test 64 megabytes input standard input output standard output In one very old text file there was written Great Wisdom. This Wisdom was so Great that nobody could decipher it, even Phon…