zoukankan      html  css  js  c++  java
  • hdu1217 Arbitrage

    Problem 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 example, suppose that 1 US Dollar buys 0.5 British pound, 1 British pound buys 10.0 French francs, and 1 French franc buys 0.21 US dollar. Then, by converting currencies, a clever trader can start with 1 US dollar and buy 0.5 * 10.0 * 0.21 = 1.05 US dollars, making a profit of 5 percent.

    Your job is to write a program that takes a list of currency exchange rates as input and then determines whether arbitrage is possible or not.
     

    Input
    The input file will contain one or more test cases. Om the first line of each test case there is an integer n (1<=n<=30), representing the number of different currencies. The next n lines each contain the name of one currency. Within a name no spaces will appear. The next line contains one integer m, representing the length of the table to follow. The last m lines each contain the name ci of a source currency, a real number rij which represents the exchange rate from ci to cj and a name cj of the destination currency. Exchanges which do not appear in the table are impossible.
    Test cases are separated from each other by a blank line. Input is terminated by a value of zero (0) for n.
     

    Output
    For each test case, print one line telling whether arbitrage is possible or not in the format "Case case: Yes" respectively "Case case: No".
     

    Sample Input
    3 USDollar BritishPound FrenchFranc 3 USDollar 0.5 BritishPound BritishPound 10.0 FrenchFranc FrenchFranc 0.21 USDollar 3 USDollar BritishPound FrenchFranc 6 USDollar 0.5 BritishPound USDollar 4.9 FrenchFranc BritishPound 10.0 FrenchFranc BritishPound 1.99 USDollar FrenchFranc 0.09 BritishPound FrenchFranc 0.19 USDollar 0
     

    Sample Output
    Case 1: Yes Case 2: No
    这题可以用floyd和map做,map用来存货币的种类,再用floyd判断经过其他货币中转到自己的时候有没有汇率大于1的情况。
    #include<stdio.h> #include<map> #include<string.h> #include<string> #include<algorithm> using namespace std; char s[100][100],s1[100],s2[100]; double dis[100][100]; int flag,n,index; double max(double a,double b) { return a>b?a:b; } void floyd() { int i,j,k; for(k=1;k<=index;k++){ for(i=1;i<=index;i++){ for(j=1;j<=index;j++){ dis[i][j]=max(dis[i][j],dis[i][k]*dis[k][j]); } } } for(i=1;i<=index;i++){ if(dis[i][i]>1){ flag=1;break; } } return; } int main() { int m,i,j,num=0; double a; while(scanf("%d",&n)!=EOF && n!=0) { map<string,int> hash; hash.clear(); memset(dis,0,sizeof(dis)); index=0; for(i=1;i<=n;i++){ scanf("%s",s[i]); if(hash[s[i]]==0){ index++; hash[s[i]]=index; } } flag=0; scanf("%d",&m); for(i=1;i<=m;i++){ scanf("%s%lf%s",s1,&a,s2); if(strcmp(s1,s2)==0 && a>1) flag=1; if(dis[hash[s1]][hash[s2]]<a){ dis[hash[s1]][hash[s2]]=a; } } printf("Case %d: ",++num); //printf("%d ",index); if(flag==1){ printf("Yes ");continue; } floyd(); if(flag)printf("Yes "); else printf("No "); } return 0; }
  • 相关阅读:
    JS基本概念 -- 操作符 -- 布尔操作符
    JS基本概念 -- 操作符 -- 一元操作符
    JS基本概念 -- 数据类型(二)
    JS基本概念 -- 数据类型(一)
    JS基本概念 -- 语法
    使用Browsersync热更新热替换,解放F5
    js中汉字utf8编码互相转换
    npm 使用代理 install 插件
    时间戳转换成yyyy-mm-dd
    Backbone.View.extend之后的构造函数实例化经历了一些什么处理
  • 原文地址:https://www.cnblogs.com/herumw/p/9464811.html
Copyright © 2011-2022 走看看