题目要求1到n点的最大容量的增广路. 听说是最短路求的,然后乱搞就A了.. 大概能从Bellman-Ford的思想,dk[u]表示从源点出发经过最多k条边到达u点的最短路,上理解正确性. #include<cstdio> #include<cstring> #include<queue> #include<algorithm> using namespace std; #define INF (1<<30) #define MAXN 1111 #…

题目电波: POJ--1797 Heavy Transportation n点m条边, 求1到n最短边最大的路径的最短边长度 改进dijikstra,dist[i]数组保存源点到i点的最短边最大的路径的最短边长度 #include<iostream> #include<cstring> #include<algorithm> #include<stdio.h> using namespace std; #define maxn 100010 #define…

Heavy Transportation Time Limit: 3000MS   Memory Limit: 30000K Total Submissions:46898   Accepted: 12204 Description Background Hugo Heavy is happy. After the breakdown of the Cargolifter project he can now expand business. But he needs a clever man…

传送门 1.最大生成树 可以求出最大生成树,其中权值最小的边即为答案. 2.最短路 只需改变spfa里面的松弛操作就可以求出答案. ——代码 #include <queue> #include <cstdio> #include <cstring> using namespace std; ; int T, n, m, cnt; int head[MAXN], next[MAXN * MAXN], to[MAXN * MAXN], val[MAXN * MAXN], d…

Background Hugo Heavy is happy. After the breakdown of the Cargolifter project he can now expand business. But he needs a clever man who tells him whether there really is a way from the place his customer has build his giant steel crane to the place…

http://poj.org/problem?id=1797 题意 :给出N个城市M条边,每条边都有容量值,求一条运输路线使城市1到N的运输量最大. 思路 :用dijkstra对松弛条件进行变形.解释一下样例吧:从1运到3有两种方案方案1:1-2-3,其中1-2承重为3,2-3承重为5,则可以运送货物的最大重量是3(当大于3时明显1到不了2)方案2:1-3,可知1-3承重为4,故此路可运送货物的最大重量是4,故答案输出4 #include <iostream> #include <std…

POJ 1797 Heavy Transportation / SCU 1819 Heavy Transportation (图论,最短路径) Description Background Hugo Heavy is happy. After the breakdown of the Cargolifter project he can now expand business. But he needs a clever man who tells him whether there reall…

3.1最短路之单源最短路(SPFA) 松弛:常听人说松弛,一直不懂,后来明白其实就是更新某点到源点最短距离. 邻接表:表示与一个点联通的所有路. 如果从一个点沿着某条路径出发,又回到了自己,而且所经过的边上的权和小于0, 就说这条路是一个负权回路. 回归正题,SPFA是bellman-ford的一种改进算法,由1994年西安交通大学段凡丁提出.它无法处理带有负环的图,判断方法:如果某个点进入队列的次数超过N次则存在负环. SPFA的两种写法,bfs和dfs,bfs判别负环不稳定,相当于限深度搜索…

Heavy Transportation Time Limit: 3000MS   Memory Limit: 30000K Total Submissions: 52728   Accepted: 13474 题目链接:http://poj.org/problem?id=1797 Description: Background Hugo Heavy is happy. After the breakdown of the Cargolifter project he can now expan…

传送门 Heavy Transportation Time Limit: 3000MS   Memory Limit: 30000K Total Submissions: 31882   Accepted: 8445 Description Background Hugo Heavy is happy. After the breakdown of the Cargolifter project he can now expand business. But he needs a clever…