心累,陕西邀请赛学校不支持,可能要自费了.. 思路:套用Bellman-Ford判断负环的思路,把大于改成小于即可判定是否存在从源点能到达的正环.如果存在正环,那么完全多跑几次正环就可以把钱增加到足够返回到S并且大于原来的金额. AC代码 #include <cstdio> #include <cmath> #include <cctype> #include <algorithm> #include <cstring> #include <…

POJ 2240 Arbitrage / ZOJ 1092 Arbitrage / HDU 1217 Arbitrage / SPOJ Arbitrage(图论,环) Description Arbitrage is the use of discrepancies in currency exchange rates to transform one unit of a currency into more than one unit of the same currency. For exa…

题目传送门 /* 最短路:Floyd模板题 只要把+改为*就ok了,热闹后判断d[i][i]是否大于1 文件输入的ONLINE_JUDGE少写了个_,WA了N遍:) */ #include <cstdio> #include <iostream> #include <cstring> #include <algorithm> #include <string> #include <map> #include <cmath>…

Arbitrage Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 21300   Accepted: 9079 Description Arbitrage is the use of discrepancies in currency exchange rates to transform one unit of a currency into more than one unit of the same currenc…

Arbitrage Time Limit: 1000MS   Memory Limit: 65536K Total Submissions:27167   Accepted: 11440 Description Arbitrage is the use of discrepancies in currency exchange rates to transform one unit of a currency into more than one unit of the same currenc…

d[i]代表从起点出发可以获得最多的钱数,松弛是d[v]=r*d[u],求最长路,看有没有正环 然后这题输入有毒,千万别用cin 因为是大输入,组数比较多,然后找字符串用strcmp就好,千万不要用map 这题刚开始我T了(用的map),还以为组数很多卡spfa呢,然后我上网看了看都是floyd的,然后我用floyd写了一发,891ms过了 然后我感觉spfa的复杂度也不是很大,就是看有没有正环,所以我觉得可能是map+cin的锅,然后改了一发,用的spfa,47ms过 真是,算了,实质是本蒟蒻…

和POJ1860差不多,就是用bellmanford判读是否存在正环,注意的是同种货币之间也可以交换,就是说:A货币换A货币汇率是2的情况也是存在的. #include<stdio.h> #include<string.h> #include<cstring> #include<string> #include<math.h> #include<queue> #include<algorithm> #include<…

Currency Exchange Time Limit:1000MS     Memory Limit:30000KB     64bit IO Format:%I64d & %I64u Submit Status Practice POJ 1860 Description Several currency exchange points are working in our city. Let us suppose that each point specializes in two par…

题目链接:http://poj.org/problem?id=3621 Sightseeing Cows Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 11526   Accepted: 3930 Description Farmer John has decided to reward his cows for their hard work by taking them on a tour of the big ci…

链接: http://poj.org/problem?id=2240 http://acm.hust.edu.cn/vjudge/contest/view.action?cid=22010#problem/F Arbitrage Time Limit: 1000MS   Memory Limit: 65536K Total Submissions: 13067   Accepted: 5493 Description Arbitrage is the use of discrepancies i…