poj 2396

有上下界的网络流，非主流做法。

#include<iostream>
#include<fstream>
#include<queue>

using namespace std;

int n;
int c[250][250],pre[250],f[250][250];
int d[250],flow;
int v[250];


typedef struct e{
	int data;
	e *next;
}e;

e edge[250];


int build(){
	int i,j,k;
	queue<int> q;
	q.push(1);
	memset(d,0,sizeof(d));
	d[1]=1;
	while(!q.empty())
	{
		i=q.front();
		q.pop();
		e *p=edge[i].next;
		while(p)
		{
			j=p->data;
			if(d[j]==0&&c[i][j]>f[i][j])
			{
				d[j]=d[i]+1;
				if(j==n) return 1;
				q.push(j);
			}
			p=p->next;
		}
	}
	return 0;
}

int find(int m,int minw){
	int i,j,k;
	if(m==n) return minw;
	v[m]=1;
	e *p=edge[m].next;
	while(p)
	{
		i=p->data;
		if(c[m][i]>f[m][i]&&d[i]==d[m]+1&&v[i]==0)
		{
			j=find(i,min(minw,c[m][i]-f[m][i]));
			if(j)
			{
				f[m][i]+=j;
				f[i][m]=-1*f[m][i];
				return j;
			}
		}
		p=p->next;
	}
	return 0;
}


int solve(){
	int i,j,k;
	 flow=0;
	memset(f,0,sizeof(f));
	while(build())
		while(1){
			memset(v,0,sizeof(v));
			i=10000000;
			k=find(1,i);
			flow+=k;
			if(k==0) break;
		}
	return flow;
}

int a[210][21];
int b[210][21];
int h1[210];
int h2[21];

void read(){
//	ifstream cin("in.txt");
	int i,j,k,s,t,value;
	int K,m;
	cin>>K;
	while(K--)
	{
		cin>>n>>m;
		int sum=0,sum2=0;
		memset(edge,0,sizeof(edge));
		memset(c,0,sizeof(c));
		memset(a,0,sizeof(a));
		memset(b,-1,sizeof(b));
		memset(h1,0,sizeof(h1));
		memset(h2,0,sizeof(h2));

		for(i=1;i<=n;i++)
		{
			cin>>c[1][i+1];
			sum+=c[1][i+1];

			e *p=new e;
			p->data=i+1;
			p->next=edge[1].next;
			edge[1].next=p;

			e* q=new e;
			q->data=1;
			q->next=edge[i+1].next;
			edge[i+1].next=q;
		}
			
		for(i=1;i<=m;i++)
		{
			cin>>c[1+n+i][n+m+2];
			sum2+=c[1+n+i][n+m+2];

			e *p=new e;
			p->data=n+m+2;
			p->next=edge[1+n+i].next;
			edge[1+n+i].next=p;

			e* q=new e;
			q->data=1+n+i;
			q->next=edge[n+m+2].next;
			edge[n+m+2].next=q;
		}
		if(sum!=sum2)
		{
			cout<<"IMPOSSIBLE"<<endl<<endl;
			continue;
		}
		cin>>k;
		char w;
		for(i=1;i<=k;i++)
		{
			cin>>s>>t>>w>>value;
			if(w=='=')
			{
				if(s==0&&t==0)
				{
					for(int i=1;i<=n;i++)
						for(int j=1;j<=m;j++)
						{
							a[i][j]=value;
							b[i][j]=value;
						}
				}
				else
					if(s==0)
					{
						
						for(int i=1;i<=n;i++)
						{
							
							a[i][t]=value;
							b[i][t]=value;
						}
					}
					else
						if(t==0)
						{
							
							for(int i=1;i<=m;i++)
							{
							
								a[s][i]=value;
								b[s][i]=value;
							}
						}
						else
						{
							
							a[s][t]=value;
							b[s][t]=value;
						}
			}
			if(w=='>')
			{
				value++;
				if(s==0&&t==0)
				{
					for(int i=1;i<=n;i++)
						for(int j=1;j<=m;j++)
						{
							
							a[i][j]=max(a[i][j],value);
							
						}
				}
				else
					if(s==0)
					{
						
						for(int i=1;i<=n;i++)
						{
							
							a[i][t]=max(a[i][t],value);
							
						}
					}
					else
						if(t==0)
						{
							
							for(int i=1;i<=m;i++)
							{
								
								a[s][i]=max(a[s][i],value);
							}
						}
						else
						{
							
							a[s][t]=max(a[s][t],value);
							
						}
			}
			if(w=='<')
			{
				value--;
				if(s==0&&t==0)
				{
					for(int i=1;i<=n;i++)
						for(int j=1;j<=m;j++)
						{
							if(b[i][j]!=-1)
								b[i][j]=min(b[i][j],value);
							else
								b[i][j]=value;
						}
				}
				else
					if(s==0)
					{
						
						for(int i=1;i<=n;i++)
						{
							if(b[i][t]!=-1)
								b[i][t]=min(b[i][t],value);
							else
								b[i][t]=value;
						}
					}
					else
						if(t==0)
						{
							
							for(int i=1;i<=m;i++)
							{
								if(b[s][i]!=-1)
								b[s][i]=min(value,b[s][i]);
								else
									b[s][i]=value;
							}
						}
						else
						{
							if(b[s][t]==-1)
							b[s][t]=value;
							else
								b[s][t]=min(b[s][t],value);
						}
			}
		}
		
		for(i=1;i<=n;i++)
			for(j=1;j<=m;j++)
			{
				if(b[i][j]==-1)
					b[i][j]=1000000;
				h1[i]+=a[i][j];
				h2[j]+=a[i][j];
				c[i+1][j+n+1]=b[i][j]-a[i][j];
				e *p=new e;
				p->data=j+n+1;
				p->next=edge[i+1].next;
				edge[i+1].next=p;

				e*q=new e;
				q->data=i+1;
				q->next=edge[j+n+1].next;
				edge[j+n+1].next=q;
			}
		for(i=1;i<=m;i++)
		{
			c[1][i+n+1]=h2[i];
			e *p=new e;
			p->data=i+n+1;
			p->next=edge[1].next;
			edge[1].next=p;

			e *q=new e;
			q->data=1;
			q->next=edge[i+n+1].next;
			edge[i+n+1].next=q;
		}
		for(i=1;i<=n;i++)
		{
			c[i+1][m+n+2]=h1[i];
			e *p=new e;
			p->data=n+m+2;
			p->next=edge[1+i].next;
			edge[1+i].next=p;

			e *q=new e;
			q->data=i+1;
			q->next=edge[m+n+2].next;
			edge[m+n+2].next=q;
		}
	
		n=n+m+2;
		solve();
		
			n-=m+2;
			int row[210];
			int colon[21];
			memset(row,0,sizeof(row));
			memset(colon,0,sizeof(colon));
			int sum1=0;
			for(i=1;i<=n;i++)
			{
				for(j=1;j<=m;j++)
				{
					row[i]+=f[i+1][j+n+1]+a[i][j];
					colon[j]+=f[i+1][j+n+1]+a[i][j];
					
				}
			}
			for(i=1;i<=n;i++)
				if(c[1][i+1]!=row[i])
				{
					sum1=1;
					break;
				}
				if(sum1==0)
			for(i=1;i<=m;i++)
				if(c[1+n+i][n+m+2]!=colon[i])
				{
					sum1=1;
					break;
				}
		if(sum1==0)
		{
			for(i=1;i<=n;i++)
			{
				for(j=1;j<=m;j++)
					cout<<f[i+1][j+n+1]+a[i][j]<<' ';
				cout<<endl;
			}
			cout<<endl;
		}
		else
			cout<<"IMPOSSIBLE"<<endl<<endl;

		
	}

}

int main(){
	read();
	return 0;
}

转载于:https://www.cnblogs.com/zhaozhe/archive/2011/03/14/1983859.html