POJ1741 Tree + BZOJ1468 Tree Description Give a tree with n vertices,each edge has a length(positive integer less than 1001). Define dist(u,v)=The min distance between node u and v. Give an integer k,for every pair (u,v) of vertices is called valid i…

题意:给一棵树,问你最多能找到几个组合(u,v),使得两点距离不超过k. 思路:点分治,复杂度O(nlogn*logn).看了半天还是有点模糊. 显然,所有满足要求的组合,连接这两个点,他们必然经过他们的最小公共子树. 参考:[poj1741]Tree 树的点分治 代码: #include<set> #include<map> #include<stack> #include<cmath> #include<queue> #include<…

Description Give a tree with n vertices,each edge has a length(positive integer less than 1001). Define dist(u,v)=The min distance between node u and v. Give an integer k,for every pair (u,v) of vertices is called valid if and only if dist(u,v) not e…

Tree Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 25286   Accepted: 8421 Description Give a tree with n vertices,each edge has a length(positive integer less than 1001).  Define dist(u,v)=The min distance between node u and v.  Give a…

Give a tree with n vertices,each edge has a length(positive integer less than 1001).Define dist(u,v)=The min distance between node u and v. Give an integer k,for every pair (u,v) of vertices is called valid if and only if dist(u,v) not exceed k. Writ…

Tree Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 25772   Accepted: 8566 Description Give a tree with n vertices,each edge has a length(positive integer less than 1001). Define dist(u,v)=The min distance between node u and v. Give an…

1 /* *********************************************** 2 Author :kuangbin 3 Created Time :2013-11-17 14:30:29 4 File Name :E:\2013ACM\专题学习\树的分治\POJ1741.cpp 5 ************************************************ */ 6 7 #include <stdio.h> 8 #include <str…

传送门 时隔一个月再次写点分治,比上一次要深入理解很多了.(虽然代码还是写不熟 模板题,不多说 //POJ 1741 //by Cydiater //2016.9.22 #include <cstdio> #include <cstring> #include <string> #include <algorithm> #include <queue> #include <map> #include <ctime> #in…

题目大意:一棵带边权无根树,边权代表距离,求距离小于等于k的点对儿数. 题目分析:这两个点之间的路径只有两种可能,要么经过根节点,要么在一棵子树内.定义depth(i)表示点 i 到根节点的距离,belong(i)表示 i 所属的子树.如果路径经过根节点,那么满足depth(i)+depth(j)<=k并且belong(i)<>belong(j)的(i,j)为一个点对儿,如果在子树内,递归到子树即可. 总的过程就变成了这样的: 1.求出所有的depth: 2.求出满足depth(i)+d…

题目链接:http://poj.org/problem?id=1741 题意:求树上两点之间距离小于等于k的点对的数量 思路:点分治模板题,推荐一篇讲的非常好的博客:https://blog.csdn.net/qq_39553725/article/details/77542223 实现代码: #include<iostream> #include<cstring> #include<algorithm> using namespace std; #define ll…