题意:有m个货币交换点,每个点只能有两种货币的互相交换,且要给佣金,给定一开始的货币类型和货币数量,问若干次交换后能否让钱增加. 思路:spfa求最长路,判断是否存在正环,如果存在则钱可以在环中一直增加,最后的钱肯定也是增加的. #include <iostream> #include <cstring> #include <queue> #include <cstdio> using namespace std; + ; struct edge{ int…

Description Several currency exchange points are working in our city. Let us suppose that each point specializes in two particular currencies and performs exchange operations only with these currencies. There can be several points specializing in the…

题目链接:http://poj.org/problem?id=1860 Currency Exchange Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 32128   Accepted: 12228 Description Several currency exchange points are working in our city. Let us suppose that each point specialize…

链接: http://poj.org/problem?id=1860 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=22010#problem/A Currency Exchange Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 16244   Accepted: 5656 Description Several currency exchange point…

MARK 用spfa判断是否存在负环 判断是否存在负环的方法有很多, 其中用spfa判断的方法是:如果存在一个点入栈两次,那么就存在负环. 细节想想确实是这样,按理来说是不存在入栈两次的如果边权值为正的话 这个算法是O(N*M) 还有一种方法是直接用bellman-ford,虽说spfa也就是bellman-ford+FIFO队列 而且bellman-ford还可以计算负环的值 顺手附上代码好了: for(int i=0;i<n;i++) d[i]=INF;//初始化 d[0]=0; for(i…

Time Limit: 1000MS   Memory Limit: 30000K Total Submissions: 16456   Accepted: 5732 Description Several currency exchange points are working in our city. Let us suppose that each point specializes in two particular currencies and performs exchange op…

Currency Exchange POJ - 1860 题意: 有许多货币兑换点,每个兑换点仅支持两种货币的兑换,兑换有相应的汇率和手续费.你有s这个货币 V 个,问是否能通过合理地兑换货币,使得你手中的货币折合成s后是有增加的. 思路: 这道题在建立每种货币的兑换关系后,找到图中的正环即可,因为你沿着正环跑就可以增加价值.这里可以用类似Bellman_Ford判断负环的方法. #include <algorithm> #include <iterator> #include &…

题目链接:http://poj.org/problem?id=1860 Description Several currency exchange points are working in our city. Let us suppose that each point specializes in two particular currencies and performs exchange operations only with these currencies. There can b…

Currency Exchange DescriptionSeveral currency exchange points are working in our city. Let us suppose that each point specializes in two particular currencies and performs exchange operations only with these currencies. There can be several points sp…

Several currency exchange points are working in our city. Let us suppose that each point specializes in two particular currencies and performs exchange operations only with these currencies. There can be several points specializing in the same pair o…