HDU 3240 Counting Binary Trees(组合数学-斯特林数,数论-整数快速幂,数论-求逆元)
题目大意:
问你不超过n个节点的二叉树的方案数,结果要对m求余。
解题思路:
方案数可以划分左右两边划分子问题也就是 h(n)=h(0)*h(n-1)+h(1)*(h-2)+..................+h(n-1)*h(0),一看就是卡特兰数,
关于卡特兰数必须要nlg^n的左右效率的算法解决
百度一下,知道:
令h(0)=1,h(1)=1,
catalan数满足:
递推式[1]...
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其他好文 时间:
2014-08-25 14:59:24
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223
There are n trees planted in lxhgww's garden. You can assume that these trees are planted along the X-axis, and the coordinate of ith tree is xi.But i...
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其他好文 时间:
2014-08-20 02:30:35
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347
Here is a class for binary trees that directly implements the recursive definition. By extending the AbstractCollectionclass, it remains consistent with the Java Collections Framework....
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其他好文 时间:
2014-08-20 00:04:26
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307
Given n, generate all structurally unique BST's (binary search trees) that store values 1...n.For example,Given n = 3, your program should return all ...
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其他好文 时间:
2014-08-18 21:58:52
阅读次数:
260
题目大意:
按照题意将数用二叉树的形式表示出来。将二叉树按照要求形式输出。
解题思路:
由于有图示,可以轻易看出这个顺序跟卡特兰数列有关。且对于任意一个树的任意子树来说,右子树相当于分针,左子树相当于秒针。也就是说当右子树要变换到下一种状态时,左子树要将它所能变换的状态全变换完才可以。
下面是代码:
#include
#include
#include
#inclu...
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其他好文 时间:
2014-08-18 09:16:33
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185
[Definitions]
Here is the recursive definition of a binary tree:
A binary tree is either the empty set or a triple T = (x,L,R), where x is a node and L and R are disjoint binary trees, neither of wh...
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其他好文 时间:
2014-08-18 01:34:43
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216
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...
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其他好文 时间:
2014-08-18 00:03:13
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189
Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical an...
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其他好文 时间:
2014-08-17 19:49:42
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190
Dream CityTime Limit:1 Second Memory Limit:32768 KBJAVAMAN is visiting Dream City and he sees a yard of gold coin trees. There arentrees in the yard. ...
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其他好文 时间:
2014-08-16 23:48:01
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245
Beautiful Garden
There are n trees planted in lxhgww's garden. You can assume that these trees are planted along the X-axis, and the coordinate of ith tree
is xi.
But in rece...
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其他好文 时间:
2014-08-16 21:10:21
阅读次数:
174