更好的阅读体验 Portal Portal1: Codeforces Portal2: Luogu Description In one very old text file there was written Great Wisdom. This Wisdom was so Great that nobody could decipher it, even Phong - the oldest among the inhabitants of Mainframe. But still he m…
传送门:http://codeforces.com/problemset/problem/9/D [题解] 树形dp,f(i,j)表示i个节点,高度为j的方案数,枚举左子树大小和哪一个子树高度为j-1即可. 不加任何优化时间复杂度$O(n^4)$ # include <bits/stdc++.h> using namespace std; typedef long long ll; ; int n, h; ll f[M][M]; int main() { cin >> n >…
For a undirected graph with tree characteristics, we can choose any node as the root. The result graph is then a rooted tree. Among all possible rooted trees, those with minimum height are called minimum height trees (MHTs). Given such a graph, write…
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 这道题实际上是Catalan Number卡塔兰数的一个例子,如果对卡塔兰数不熟悉的童鞋可能真…
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 5 unique BST's shown below. 1 3 3 2 1 \ / / / \ \ 3 2 1 1 3 2 / / \ \ 2 1 2 3 confused what "{1,#,2…
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 5 unique BST's shown below. 1 3 3 2 1 \ …
http://staff.city.ac.uk/~ross/papers/FingerTree.html Summary We present 2-3 finger trees, a functional representation of persistent sequences supporting access to the ends in amortized constant time, and concatenation and splitting in time logarithmi…
