Cod sursa(job #252810)

Utilizator yoyolichIoana Ardeleanu yoyolich Data 4 februarie 2009 22:20:44
Problema Flux maxim Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 1.25 kb
#include<stdio.h>
#include<vector>
#define nmax 1024
#define oo 0x3f3f3f3f
using namespace std;

int n,m,C[nmax][nmax],viz[nmax],flow,fmin,x,y,z,tata[nmax],F[nmax][nmax],i;
int Q[nmax];
vector<int> G[nmax];


inline int bfs()
{
	int x,i,j;

	memset(viz,0,sizeof(viz));
	Q[0]=1;
	Q[1]=1;
	viz[1]=1;
	for(j=1;j<=Q[0];++j)
	{
		x=Q[j];
		if(x==n) continue;
		for(i=0;i<G[x].size();i++)
				{
					
					if (C[x][G[x][i]] == F[x][G[x][i]] || viz[G[x][i]]) continue;  
					Q[++Q[0]]=G[x][i];
					tata[G[x][i]]=x;
					viz[G[x][i]]=1;
				}
	}
	return viz[n];
}

int main()
{

	freopen("maxflow.in","r",stdin);
	freopen("maxflow.out","w",stdout);
	scanf("%d %d",&n,&m);
	for(i=1;i<=m;i++)
	{
		scanf("%d %d %d",&x,&y,&z);
		G[x].push_back(y);
		G[y].push_back(x);
		C[x][y]+=z;
	}
	
	flow=0;
	while(bfs())
	   for(i=0; i < G[n].size() ;i++)
		{
		if (F[G[n][i]][n] == C[G[n][i]][n] || !viz[G[n][i]]) continue;
		tata[n]=G[n][i];
		
		fmin=oo;
		for(i=n;i!=1;i=tata[i])
		{
			fmin=min(fmin, C[tata[i]][i]-F[tata[i]][i]);
		}
		if (fmin == 0) continue;
		
		for(i=n;i!=1;i=tata[i])
		{
			F[tata[i]][i]+=fmin;
			F[i][tata[i]]-=fmin;
		}
		
		flow+=fmin;
	}

	printf("%d\n",flow);
	
	return 0;
}