POJ2396 Budget 题意:n*m的非负整数矩阵,给出每行每列的和,以及一些约束关系x,y,>=<,val,表示格子(x,y)的值与val的关系,0代表整行/列都有这个关系,求判断是否有解并求一组解 建图显然 \[s \rightarrow _{[行和,行和]} x \rightarrow _{格子(x,y)的限制[l,r]} y \rightarrow_{[列和,列和]} t\] 有源汇上下界可行流 注意是非负整数 #include <iostream> #include…

Budget Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 5962   Accepted: 2266   Special Judge Description We are supposed to make a budget proposal for this multi-site competition. The budget proposal is a matrix where the rows represent…

Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 7401   Accepted: 2764   Special Judge Description We are supposed to make a budget proposal for this multi-site competition. The budget proposal is a matrix where the rows represent differe…

Budget Time Limit: 5 Seconds      Memory Limit: 32768 KB      Special Judge We are supposed to make a budget proposal for this multi-site competition. The budget proposal is a matrix where the rows represent different kinds of expenses and the column…

Budget Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 8946   Accepted: 3327   Special Judge 题目链接:http://poj.org/problem?id=2396 Description: We are supposed to make a budget proposal for this multi-site competition. The budget proposal…

Budget:http://poj.org/problem?id=2396 题意: 给定一个棋盘,给定每一行每一列的和,还有每个点的性质.求一个合理的棋盘数值放置方式. 思路: 比较经典的网络流模型,把每一列看成一个点,每一行看成一个点,利用上下界可行流的思路建图就行了,注意这里由于是严格的小于和大于,所以可以利用 x+1, x-1. 还有就是这道题的0 , 0 说的是对整张图的操作. #include <algorithm> #include <iterator> #includ…

题目大概给一个有n×m个单元的矩阵,各单元是一个非负整数,已知其每行每列所有单元的和,还有几个约束条件描述一些单元是大于小于还是等于某个数,问矩阵可以是怎样的. 经典的流量有上下界网络流问题. 把行.列看成点,各单元看成边 源点向各行连容量下界0上界该行和的边,各列向汇点连容量下界0上界该列和的边 对于各单元,其对应行列表示的边间连下界上界和约束条件对应的边 这样就是求解这个网络的可行流,可以通过汇点向源点连容量INF的边,使各个顶点都满足平衡条件,这样转化成无源汇有上下界网络流来求解. 最后就…

[题目链接] http://poj.org/problem?id=2396 [题意] 知道一个矩阵的行列和,且知道一些格子的限制条件,问一个可行的方案. [思路] 设行为X点,列为Y点,构图:连边(s,Xi,sumXi,sumXi)(Yi,t,sumYi,sumYi)(Xi,Yj,down[i][j],up[i][j]). 则问题就是求一个有源汇点st的上下界可行流. 类似于 无源无汇上下界可行流 ,添加附加源汇点ST,边权转化为up-down,由ST向每个点连边保持流量平衡.然后添加(t,s,…

Description We are supposed to make a budget proposal for this multi-site competition. The budget proposal is a matrix where the rows represent different kinds of expenses and the columns represent different sites. We had a meeting about this, some t…

http://poj.org/problem?id=2396 (题目链接) 题意 给出一个矩阵,给出每一行每一列的和,以及若干限制条件,限制了其中每一个元素的上下界,求一种可行的方案使得每一行每一列数的和满足要求. Solution 我已经完全没有网络流思维了,江化了= .= 源点向每一行和每一列连上下界都为其对应和的边,行与列之间连边,边的上下界为对应格子的取值范围.然后跑上下界网络流找一条可行流就可以了. 细节 mdzz初值设太大爆int了=  =,还有这种事.. 代码 // poj2396…