OJ-Problems-Source/HDOJ/3616_autoAC.cpp

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#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
const int maxn = 40;
const int maxpot = maxn*maxn*2;
const int maxm = maxpot*10;
const int INFI = 99999999;
const int dx[4] = {0,1,0,-1};
const int dy[4] = {1,0,-1,0};
int a[maxn][maxn];
int idx[maxn][maxn];
int L[maxpot],R[maxpot];
int head[maxpot],dep[maxpot],lis[maxpot];
int ne[maxm],pot[maxm],flow[maxm];
int S,T,tot,n,m;
void addedge(int a,int b,int c)
{
pot[++tot] = b; ne[tot] = head[a];
head[a] = tot; flow[tot] = c;
}
void connect(int a,int b,int c)
{
addedge(a,b,c);
addedge(b,a,0);
}
bool bfs()
{
for (int i=0;i<=T;i++) dep[i] = 0;
int h=1,t=1;
lis[1] = S;
dep[S] = 1;
while ( h<=t )
{
int v = lis[h];
for (int e=head[v];e!=-1;e=ne[e])
if ( flow[e]>0 && dep[pot[e]]==0 )
{
dep[pot[e]] = dep[v] + 1;
lis[++t] = pot[e];
}
h++;
}
return dep[T]>0;
}
int findpath(int v,int tmpflow)
{
if ( v==T ) return tmpflow;
int rec = 0,tmp;
for (int e=head[v];e!=-1;e=ne[e])
if ( flow[e]>0 && dep[pot[e]]==dep[v]+1 )
{
tmp = findpath(pot[e],min(tmpflow,flow[e]));
tmpflow -= tmp; rec += tmp;
flow[e] -= tmp; flow[e^1] += tmp;
if ( tmpflow==0 ) break;
}
dep[v] = 0;
return rec;
}
int dinic()
{
int ret = 0;
while ( bfs() )
ret += findpath(S,INFI);
return ret;
}
void build_graph()
{
int sum = 0;
int tx,ty;
int v,u;
for (int i=0;i<n;i++)
for (int j=0;j<m;j++)
if ( a[i][j]!=-1 )
idx[i][j] = ++sum;
S = 0;
for (int i=1;i<=sum;i++)
{
L[i] = i;
R[i] = i + sum;
}
T = 2 * sum + 1;
memset(head,-1,sizeof(head));
tot = -1;
for (int i=0;i<n;i++)
for (int j=0;j<m;j++)
if ( a[i][j]!=-1 )
{
v = idx[i][j];
if ( a[i][j]!=0 )
connect(L[v],R[v],a[i][j]);
else
connect(L[v],R[v],INFI);
for (int t=0;t<4;t++)
{
tx = i + dx[t];
ty = j + dy[t];
if ( tx<0 || ty<0 || tx>=n || ty>=m ) continue;
u = idx[tx][ty];
if ( a[tx][ty]!=-1 )
connect(R[v],L[u],INFI);
}
if ( a[i][j]==0 )
connect(S,L[v],INFI);
if ( i==0 || j==0 || i==n-1 || j==m-1 )
connect(R[v],T,INFI);
}
}
int main()
{
int test;
scanf("%d",&test);
for (int cas=1;cas<=test;cas++)
{
scanf("%d%d",&n,&m);
for (int i=0;i<n;i++)
for (int j=0;j<m;j++)
scanf("%d",&a[i][j]);
build_graph();
int ans = dinic();
printf("%d\n",ans);
}
}