COGS732. [Network Flow 24 questions] questions library

«Problem Description:
Suppose there is an n-question in a question bank. Each question is marked with the category. There may be multiple category properties for the same topic. Now from the question bank to extract the M-track composition test paper. The test paper is required to contain the specified type of question. Try to design a group volume algorithm that satisfies the requirement.
«Programming Tasks:
For a given set of volume requirements, calculate the group volume scheme that meets the requirements.
«Data Entry:
The input data is provided by the file testlib.in. The 1th line of the file has 2 positive integers k and n (2 <=k<=, k<=n<=) k indicates the total number of questions in the question bank, and N indicates the total number of questions in the question. The 2nd line has k positive integers, and the I positive integers represent the number of the type I to select. The sum of the K numbers is the total number of questions m to be selected. The next n lines give the type information of each question in the bank. The 1th positive integer p in each row indicates that the problem can belong to the P class, and then the number of P is the type number to which the problem belongs.
«Result Output:
Output the group volume scheme to file Testlib.out at the end of the program run. The first line of the file outputs "I:" followed by the number of type I. If there are multiple scenarios that meet the requirements, just output 1 scenarios. If the problem is not solved, output "nosolution!".
Input File Example
Testlib.in
3 15
3 3 4
2 1 2
1 3
1 3
1 3
1 3
3 1 2 3
2 2 3
2 1 3
1 2
1 2
2 1 2
2 1 3
2 1 2
1 1
3 1 2 3

Output File Example

Testlib.out

1:1 6 8
2:7 9 10
3:2 3 4 5

Maximum flow of network streams

If the maximum flow is equal to M, then there is a solution that iterates through all the sides of the question, and records the answer.

1 /*by Silvern*/2#include <iostream>3#include <algorithm>4#include <cstring>5#include <cstdio>6#include <cmath>7#include <vector>8#include <queue>9 using namespacestd;Ten Const intinf=1e9; One Const intmxn=1050; A intRead () { -     intx=0, f=1;CharCh=GetChar (); -      while(ch<'0'|| Ch>'9'){if(ch=='-') f=-1; ch=GetChar ();} the      while(ch>='0'&& ch<='9') {x=x*Ten+ch-'0'; ch=GetChar ();} -     returnx*F; - } - structedge{ +     intv,nxt,f; -}e[mxn* the]; + inthd[mxn],mct=1; A voidAdd_edge (intUintVintf) { ate[++mct].v=v;e[mct].nxt=hd[u];e[mct].f=f;hd[u]=MCT; -   -     return; - } - voidInsertintUintVintf) { -Add_edge (u,v,f); Add_edge (V,u,0);return; in } - intn,k,s,t; to intD[MXN]; + BOOLBFS () { -memset (D,0,sizeofd); thequeue<int>Q; * Q.push (S); $d[s]=1;Panax Notoginseng      while(!Q.empty ()) { -         intu=Q.front (); Q.pop (); the          for(intI=hd[u];i;i=e[i].nxt) { +             intv=e[i].v; A             if(!d[v] &&e[i].f) { thed[v]=d[u]+1; + Q.push (v); -             } $         } $     } -     returnD[t]; - } the intDFS (intUintLim) { -     if(u==t)returnLim;Wuyi     inttmp,f=0; the      for(intI=hd[u];i;i=e[i].nxt) { -         intv=e[i].v; Wu         if(d[v]==d[u]+1&&e[i].f) { -tmp=DFS (V,min (LIM,E[I].F)); Aboute[i].f-=tmp; $e[i^1].f+=tmp; -lim-=tmp; -f+=tmp; -             if(!lim)returnF; A         } +     } thed[u]=0; -     returnF; $ } the intDinic () { the     intres=0; the      while(BFS ()) res+=DFS (s,inf); the     returnRes; - } invector<int>Q[MXN]; the voidPrint () { the     inti,j; About      for(i=1; i<=k;i++){ the          for(j=hd[i];j;j=e[j].nxt) { the //printf ("u:%d v:%d f:%d\n", i,e[j].v,e[j].f); the             if(e[j^1].F) Q[i].push_back (e[j].v-k); +         } -     } the      for(i=1; i<=k;i++){Bayiprintf"%d:", i); the          for(j=0; J<q[i].size (); j + +){ theprintf"%d", Q[i][j]); -         } -printf"\ n"); the     } the     return; the } the intm=0; - intMain () { theFreopen ("testlib.in","R", stdin); theFreopen ("Testlib.out","W", stdout); the     inti,j;94K=read (); n=read (); thes=0; t=k+n+1; the     intx, y; the      for(i=1; i<=k;i++){98x=read (); About Insert (s,i,x); -m+=x;101     }102      for(i=1; i<=n;i++){103y=read ();104          for(j=1; j<=y;j++){ thex=read ();106Insert (X,i+k,1);107         }108     }109      for(i=1; i<=n;i++) Insert (i+k,t,inf); the     intans=dinic ();111     if(ans==m) Print (); the     Elseprintf"nosolution!\n");113     return 0; the}

COGS732. [Network Flow 24 questions] questions library