求最短路的算法最有名的是Dijkstra.所以一般拿到题目第一反应就是使用Dijkstra算法.但是此题要求的好几对起点和终点的最短路径.所以用Floyd是最好的选择.因为其他三种最短路的算法都是单源的. 输出字典序最小的路径则需要修改模版. #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> using namespace std; , INF=; int Ma…

Minimum Transport Cost Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 10029    Accepted Submission(s): 2716 Problem Description These are N cities in Spring country. Between each pair of cities…

Minimum Transport Cost http://acm.hdu.edu.cn/showproblem.php?pid=1385 Problem Description These are N cities in Spring country. Between each pair of cities there may be one transportation track or none. Now there is some cargo that should be delivere…

Minimum Transport Cost Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 8860    Accepted Submission(s): 2331 Problem Description These are N cities in Spring country. Between each pair of cities…

Minimum Transport Cost Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 8794    Accepted Submission(s): 2311 Problem Description These are N cities in Spring country. Between each pair of cities…

Minimum Transport CostTime Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 12860    Accepted Submission(s): 3633 Problem DescriptionThese are N cities in Spring country. Between each pair of cities t…

题目链接: https://vjudge.net/problem/ZOJ-1456 These are N cities in Spring country. Between each pair of cities there may be one transportation track or none. Now there is some cargo that should be delivered from one city to another. The transportation f…

题目大意 求多组i到j的最短路径 并输出字典序最小.... 现在只会floyd的方式 利用dis[i][j] 表示i到j的路径中i 后面的节点 更新是比较dis[i][j] dis[i][k]. 记住这个就好 ,其余存法貌似会有问题.代码如下: #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include <ctime> #include <…

<题目链接> 题目大意:给你一张图,有n个点,每个点都有需要缴的税,两个直接相连点之间的道路也有需要花费的费用.现在进行多次询问,给定起点和终点,输出给定起点和终点之间最少花费是多少,并且输出最少花费所走的路径,如果有多条路径花费最少,则输出字典序最小的那条. 解题分析: 输出最短路的路径问题,需要注意的是,题目要求输出的最短路径的字典序最小,所以我们在每次松弛的时候,都需要加上判断.如果有多个点的最短路相同,则用DFS求出它们之前走过的路径,并且进行比较,然后选字典序最小的那条. #incl…

http://acm.hdu.edu.cn/showproblem.php? pid=1385 求最短路.要求输出字典序最小的路径. spfa:拿一个pre[]记录前驱,不同的是在松弛的时候.要考虑和当前点的dis值相等的情况,解决的办法是dfs找出两条路径中字典序较小的.pre[]去更新. 把路径当做字符串处理. 我仅仅用之前的pre去更新当前点,并没考虑到起点到当前点的整个路径,事实上这样并不能保证是字典序最小.wa了N次.于是乎搜了下题解,发现用spfa解的非常少.看到了某大牛的解法如上,…