TYOI Day1 travel：Tree dp【处理重复走边】

【TYOI Day1 travel：Tree dp【处理重复走边】】的更多相关文章

TYOI Day1 travel：Tree dp【处理重复走边】

题意: 给你一棵树,n个节点,每条边有长度. 然后有q组询问(u,k),每次问你:从节点u出发,走到某个节点的距离mod k的最大值. 题解: 对于无根树上的dp,一般都是先转成以1为根的有根树,然后分别从上到下和从下到上两遍dp. 另一个技巧是:处理重复走边的情况时,可以让dp值表示达到某种状态的方案数. 表示状态: dp[i][j][k] = max dis 表示从i节点出发,走的距离mod k = j时的方案数找出答案: 对于每次询问(u,k),答案为:满足dp[u][d][k]>0的最…

96. Unique Binary Search Trees (Tree; DP)

Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 法I:后序遍历.同Unique Binary Search Trees II,只是现在…

HDU 4359——Easy Tree DP?——————【dp+组合计数】

Easy Tree DP? Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 1460 Accepted Submission(s): 557 Problem Description A Bear tree is a binary tree with such properties : each node has a value o…

HDU 4359 Easy Tree DP?

Easy Tree DP? Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 1487 Accepted Submission(s): 567 Problem Description A Bear tree is a binary tree with such properties : each node has a value o…

poj 3230 Travel（dp）

Description One traveler travels among cities. He has to pay for this while he can get some incomes. Now there are n cities, and the traveler has m days for traveling. Everyday he may go to another city or stay there and pay some money. When he come…

Codeforces 442D Adam and Tree dp (看题解)

Adam and Tree 感觉非常巧妙的一题.. 如果对于一个已经建立完成的树, 那么我们可以用dp[ i ]表示染完 i 这棵子树, 并给从fa[ i ] -> i的条边也染色的最少颜色数. mnson[ i ][ 0 ] 和 mnson[ i ][ 1 ]分别表示 i 的儿子的dp值的最大和第二大的值, 那么dp[ i ] = max(mnson[ i ][ 0 ], mnson[ i ][ 1 ] + 1) 根据树链剖分的原理我们知道dp的最大值不超过log(n), 那么每次加入一个新的…