zoukankan      html  css  js  c++  java
  • Reactor Cooling(无源汇有上下界网络流)

    194. Reactor Cooling

    time limit per test: 0.5 sec. 
    memory limit per test: 65536 KB
    input: standard 
    output: standard




    The terrorist group leaded by a well known international terrorist Ben Bladen is buliding a nuclear reactor to produce plutonium for the nuclear bomb they are planning to create. Being the wicked computer genius of this group, you are responsible for developing the cooling system for the reactor. 

    The cooling system of the reactor consists of the number of pipes that special cooling liquid flows by. Pipes are connected at special points, called nodes, each pipe has the starting node and the end point. The liquid must flow by the pipe from its start point to its end point and not in the opposite direction. 

    Let the nodes be numbered from 1 to N. The cooling system must be designed so that the liquid is circulating by the pipes and the amount of the liquid coming to each node (in the unit of time) is equal to the amount of liquid leaving the node. That is, if we designate the amount of liquid going by the pipe from i-th node to j-th as f ij, (put f ij = 0 if there is no pipe from node i to node j), for each i the following condition must hold: 


    sum(j=1..N, f ij) = sum(j=1..N, f ji


    Each pipe has some finite capacity, therefore for each i and j connected by the pipe must be f ij ≤ c ij where c ij is the capacity of the pipe. To provide sufficient cooling, the amount of the liquid flowing by the pipe going from i-th to j-th nodes must be at least l ij, thus it must be f ij ≥ l ij

    Given c ij and l ij for all pipes, find the amount f ij, satisfying the conditions specified above. 

    Input

    The first line of the input file contains the number N (1 ≤ N ≤ 200) - the number of nodes and and M — the number of pipes. The following M lines contain four integer number each - i, j, l ij and c ij each. There is at most one pipe connecting any two nodes and 0 ≤ l ij ≤ c ij ≤ 10 5 for all pipes. No pipe connects a node to itself. If there is a pipe from i-th node to j-th, there is no pipe from j-th node to i-th. 

    Output

    On the first line of the output file print YES if there is the way to carry out reactor cooling and NO if there is none. In the first case M integers must follow, k-th number being the amount of liquid flowing by the k-th pipe. Pipes are numbered as they are given in the input file. 

    Sample test(s)

    Input
     
     
    Test #1 

    4 6 
    1 2 1 2 
    2 3 1 2 
    3 4 1 2 
    4 1 1 2 
    1 3 1 2 
    4 2 1 2 

    Test #2 

    4 6 
    1 2 1 3 
    2 3 1 3 
    3 4 1 3 
    4 1 1 3 
    1 3 1 3 
    4 2 1 3 
     
     

    Output
     
     
    Test #1 

    NO 

    Test #2 

    YES 





     
    就是裸的吧,可以满足输出YES,并且每条的流量,如果不行,输出no。
    建边:

    然后跑一次最大流,判断是不是大于等于sum(即最小下界流量和),然后输出即可。

  • 相关阅读:
    聊聊面试-NoClassDefFoundError 和 ClassNotFoundException 区别
    聊聊面试-int和Integer的区别
    数据库char varchar nchar nvarchar,编码Unicode,UTF8,GBK等,Sql语句中文前为什么加N(一次线上数据存储乱码排查)
    SQL Server数据库阻塞,死锁查询
    数据误操作,教你使用ApexSQLLog工具从 SQLServer日志恢复数据!
    IDEA将Maven项目中指定文件夹下的xml等文件编译进classes
    Tomcat 中文乱码,设置UTF-8
    C#实现前向最大匹、字典树(分词、检索)
    23种设计模式汇总
    Head First设计模式——原型模式和访问者模式
  • 原文地址:https://www.cnblogs.com/fengzhiyuan/p/7944470.html
Copyright © 2011-2022 走看看