Basic network flow ::: MaximumFlow ---> Ford Fulkarson :: Uva problem : 820 - Internet Bandwidth(Ford Fulkarson)

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define INF 2000000
#define size 105

int mat[size][size],p[size],s,t,N,fm,Q[size],F,R;
bool tst[size];

bool AUG_PATH()
{
int i,u;

memset(tst,true,sizeof(bool)*N);
memset(p,0,sizeof(int)*(N+2));

F=R=0;
Q[R++]=s;
tst[s] = false;

while(F<R)
{
u = Q[F++];
for(i=1;i<N;i++)
if(tst[i] && mat[u][i])
{
p[i] = u;
tst[i] = false;
Q[R++] = i;
if(i==t)
return true;
}
}

return false;
}

void MAKE_RES(int u)
{
if(!p[u]) return ;

if(mat[p[u]][u]<fm) fm = mat[p[u]][u];

MAKE_RES(p[u]);
mat[p[u]][u] -= fm;
mat[u][p[u]] += fm;
}



int FORDFULKERSON()
{
int mflow=0;

while(AUG_PATH())
{
fm=INF;
MAKE_RES(t);
mflow += fm;
}
return mflow;
}


int main()
{
int i,m,T=1,n,j,u,v,c;

while(scanf("%d",&n)==1 && n)
{
N=n+1;
scanf("%d%d%d",&s,&t,&m);

for(i=1;i<N;i++)
memset(mat[i],0,sizeof(int)*N);

while(m--)
{
scanf("%d%d%d",&u,&v,&c);
mat[u][v] += c;
mat[v][u] += c;
}
printf("Network %d\nThe bandwidth is %d.\n\n",T++,FORDFULKERSON());
}

return 0;
}