一.题目 POJ2387 二.分析 Bellman-Ford算法 该算法是求单源最短路的,核心思想就是不断去更新到起点的最短距离,更新的前提是没有负边.如果有负边需要手动控制循环次数. Dijkstra算法 同样是单源最短路,它的核心是 (1) 找到最短距离已经确定的顶点,再从该顶点出发,更新与它相邻的点的最短距离. (2) 对于最短距离已经确定的点不再更新. Floyd算法 可以求解任意两点之间的最短距离.但是这题会TLE. 三.AC代码 1 #include <iostream> 2 #i…

Til the Cows Come Home 最短路Dijkstra+bellman(普通+优化) 贝西在田里,想在农夫约翰叫醒她早上挤奶之前回到谷仓尽可能多地睡一觉.贝西需要她的美梦,所以她想尽快回来. 农场主约翰的田里有n(2<=n<=1000)个地标,唯一编号为1..n.地标1是谷仓:贝西整天站在其中的苹果树林是地标n.奶牛在田里行走时使用地标间不同长度的T(1<=t<=2000)双向牛道.贝西对自己的导航能力没有信心,所以一旦开始,她总是沿着一条从开始到结束的路线行进. 根…

AC代码 POJ2387 Til the Cows Come Home Bessie is out in the field and wants to get back to the barn to get as much sleep as possible before Farmer John wakes her for the morning milking. Bessie needs her beauty sleep, so she wants to get back as quickly…

题目链接: http://poj.org/problem?id=2387 Description Bessie is out in the field and wants to get back to the barn to get as much sleep as possible before Farmer John wakes her for the morning milking. Bessie needs her beauty sleep, so she wants to get ba…

Time Limit:1000MS     Memory Limit:65536KB     64bit IO Format:%lld & %llu Description Bessie is out in the field and wants to get back to the barn to get as much sleep as possible before Farmer John wakes her for the morning milking. Bessie needs he…

题目链接:http://poj.org/problem?id=2387 题意:有n个城市点,m条边,求n到1的最短路径.n<=1000; m<=2000 就是一个标准的最短路模板. #include<iostream> #include<algorithm> #include<cstring> #include<vector> #include<queue> using namespace std; ; const int INF =…

Dijkstra模板题,也可以用Floyd算法. 关于Dijkstra算法有两种写法,只有一点细节不同,思想是一样的. 写法1: #include <iostream> #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #define Mod 1000000007 using namespace std; #define N 1007 int mp…

Til the Cows Come Home 题目链接: http://acm.hust.edu.cn/vjudge/contest/66569#problem/A Description Bessie is out in the field and wants to get back to the barn to get as much sleep as possible before Farmer John wakes her for the morning milking. Bessie…

Til the Cows Come Home Description Bessie is out in the field and wants to get back to the barn to get as much sleep as possible before Farmer John wakes her for the morning milking. Bessie needs her beauty sleep, so she wants to get back as quickly…

A - Til the Cows Come Home Time Limit:1000MS     Memory Limit:65536KB     64bit IO Format:%I64d & %I64u Submit Status Practice POJ 2387 Description Bessie is out in the field and wants to get back to the barn to get as much sleep as possible before F…