解题关键:求树上三点间的最短距离. 解题关键:$ans = (dis(a,b) + dis(a,c) + dis(b,c))/2$ //#pragma comment(linker, "/STACK:1024000000,1024000000") #include<cstdio> #include<cstring> #include<algorithm> #include<cstdlib> #include<cmath> #i…

Design the city Time Limit: 1 Second      Memory Limit: 32768 KB Cerror is the mayor of city HangZhou. As you may know, the traffic system of this city is so terrible, that there are traffic jams everywhere. Now, Cerror finds out that the main reason…

Design the city Time Limit: 1 Second      Memory Limit: 32768 KB Cerror is the mayor of city HangZhou. As you may know, the traffic system of this city is so terrible, that there are traffic jams everywhere. Now, Cerror finds out that the main reason…

题目大概说给一棵树,每次询问三个点,问要把三个点连在一起的最少边权和是多少. 分几种情况..三个点LCA都相同,三个点有两对的LCA是某一点,三个点有两对的LCA各不相同...%……￥…… 画画图可以发现..虽然好像不太严谨..连接(a,b,c)三个点的最短边权和=(dist(a,b)+dist(b,c)+dist(a,c))/2,而dist(u,v)的计算可以预处理出各点到根的距离weight,dist(u,v)=weight(u)+weight(v)-2*weight(lca(u,v))..…

Cerror is the mayor of city HangZhou. As you may know, the traffic system of this city is so terrible, that there are traffic jams everywhere. Now, Cerror finds out that the main reason of them is the poor design of the roads distribution, and he wan…

题意:给定n个点,下面n-1行 u , v ,dis 表示一条无向边和边权值,这里给了一颗无向树 下面m表示m个询问,问 u v n 三点最短距离 典型的LCA转RMQ #include<stdio.h> #include<string.h> #include<math.h> #define N 100000 #define INF 1<<29 #define Logo 17 using namespace std; inline int Min(int a…

题目链接 给一棵树, m个询问, 每个询问给出3个点, 求这三个点之间的最短距离. 其实就是两两之间的最短距离加起来除2. 倍增的lca模板 #include <iostream> #include <vector> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> #include <map> #include <s…

题目链接 : ZOJ Problem Set - 3195 题目大意: 求三点之间的最短距离 思路: 有了两点之间的最短距离求法,不难得出: 对于三个点我们两两之间求最短距离 得到 d1 d2 d3 那么最短距离就是 d = ( d1 + d2 + d3 ) / 2 要注意每个数组的范围大小,因为这个问题手抖敲错,TLE+RE一整页/(ㄒoㄒ)/~~ 用前向星来保存边和询问,空间卡的也很严 如下图所示:所求路线为紫色,等于蓝色+黄色+绿色之和的一半 代码: #include <bits/stdc…

C - Design the city Time Limit:1000MS     Memory Limit:32768KB     64bit IO Format:%lld & %llu Description Cerror is the mayor of city HangZhou. As you may know, the traffic system of this city is so terrible, that there are traffic jams everywhere.…

Design the city Time Limit: 1 Second      Memory Limit: 32768 KB Cerror is the mayor of city HangZhou. As you may know, the traffic system of this city is so terrible, that there are traffic jams everywhere. Now, Cerror finds out that the main reason…