dfs找出所有节点所在树及到树根的距离及深度及父亲. i和j在一棵树上,则最短路为dis[i]+dis[j]-dis[LCA(i,j)]*2. #include <cstring> #include <cstdio> #define N 10005 #define add(u,v,w) e[++cnt]=(edge){v,head[u],w};head[u]=cnt using namespace std; struct edge{ int to,next,w; }e[N<&…

卡特兰数 递推公式:h(n)=h(n-1)*(4*n-2)/(n+1); import java.math.BigInteger; import java.util.Scanner; public class Main { public static void main(String args[]) { Scanner cin = new Scanner(System.in); BigInteger[] c = new BigInteger[101]; c[1] = BigInteger.val…

题目代号:HDU 1134 题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=1134 Game of Connections Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 4668    Accepted Submission(s): 2729 Problem Description Thi…

Connections between cities Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 4425    Accepted Submission(s): 1263 Problem Description After World War X, a lot of cities have been seriously damag…

[题目链接]http://acm.hdu.edu.cn/showproblem.php?pid=1134 [解题背景]这题不会做,自己推公式推了一段时间,将n=3和n=4的情况列出来了,只发现第n项与第n-1项有关系,上网搜索的时候发现是组合数学中关于Catalan(卡特兰)数的运用. 以下资料来自网络,整理以备记录学习: [来源链接] http://baike.baidu.com/view/2499752.htm http://blog.163.com/lz_666888/blog/stati…

主要考察卡特兰数,大数乘法,除法…… 链接http://acm.hdu.edu.cn/showproblem.php?pid=1134 #include<iostream>#include<stdio.h>#include<algorithm>#include<cmath>#include<iomanip>;}…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=2874 题意是给你n个点,m条边(无向),q个询问.接下来m行,每行两个点一个边权,而且这个图不能有环路.然后接下来q行,每行给你两个点,问你这两个点的最短距离是多少,要是不相连,则输出一串英文. 首先想到的是用(二分)倍增LCA,但是这题的坑点是两个点可能不在同一个图中,所以我dfs的时候用block[i]标记这个点属于哪一个图中,要是这个点在同一个图中,答案就是cost[u] + cost[v]…

Connections between cities [题目链接]Connections between cities [题目类型]LCA Tarjan &题意: 输入一个森林,总节点不超过N(N<10000),由C次询问(C<1000000),每次询问两个点,如果来联通输出,两点之间的距离,如果不来联通,输出"Not connected" &题解: md,就没人吐槽这题询问时有相等的情况吗?我被这个坑了一天= = 最后把ans数组置为-1才过的,以前一直初…

http://acm.hdu.edu.cn/showproblem.php?pid=2874 题意: 求两个城市之间的距离. 思路: LCA题,注意原图可能不连通. 如果不了解离线算法的话,可以看我之前博客写的解释http://www.cnblogs.com/zyb993963526/p/7295894.html #include<iostream> #include<algorithm> #include<cstring> #include<cstdio>…

Connections between cities Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Problem Description After World War X, a lot of cities have been seriously damaged, and we need to rebuild those cities. However, some mat…