Cod sursa(job #785909)

Utilizator SebiSebiPirtoaca George Sebastian SebiSebi Data 10 septembrie 2012 10:05:08
Problema Flux maxim Scor 70
Compilator cpp Status done
Runda Arhiva educationala Marime 1.18 kb
#include<iostream>
#include<fstream>
#include<vector>
#include<string.h>
using namespace std;
const int NMAX = 1001;
int c[NMAX][NMAX],flux[NMAX][NMAX],cd[NMAX],viz[NMAX],p[NMAX],n;
vector <int> v[NMAX];
int bfs()
{
	int nod,st,dr;
	memset(viz,0,sizeof(viz));
	cd[1]=1;
	viz[1]=1;
	st=1;
	dr=1;
	while(st<=dr) {
		nod=cd[st];
		st++;
		for(vector <int> :: iterator it=v[nod].begin();it!=v[nod].end();it++) 
			if(viz[*it]==0 && c[nod][*it]>flux[nod][*it]) {
				viz[*it]=1;
				cd[++dr]=*it;
				p[*it]=nod;
				if(*it==n)
					return 1;
			}
	}
	return 0;
}
int main () 
{
	int m,i,x,y,capacity,fluxmax,fluxcurent,nod;
	ifstream f("maxflow.in");
	ofstream g("maxflow.out");
	f>>n>>m;
	for(i=1;i<=m;i++) {
		f>>x>>y>>capacity;
		v[x].push_back(y);
		v[y].push_back(x);
		c[x][y]=capacity;
	}
	f.close();
	for(fluxmax=0 ; bfs(); fluxmax=fluxmax+fluxcurent) {
		fluxcurent=(1<<30);
		for(nod=n;nod!=1;nod=p[nod]) 
			fluxcurent=min(fluxcurent,c[p[nod]][nod]-flux[p[nod]][nod]);
		for(nod=n;nod!=1;nod=p[nod]) {
			flux[p[nod]][nod]=flux[p[nod]][nod]+fluxcurent;
			flux[nod][p[nod]]=flux[nod][p[nod]]-fluxcurent;
		}
	}
	g<<fluxmax;
	g.close();
	return 0;
}