Cod sursa(job #822580)

Utilizator lianaliana tucar liana Data 23 noiembrie 2012 19:39:17
Problema Algoritmul Bellman-Ford Scor 50
Compilator cpp Status done
Runda Arhiva educationala Marime 1.33 kb
#include <stdio.h>
#include<set>
#include<utility>
#include<vector>
using namespace std;
#define nmax 50005
#define inf 1<<30
struct element{long n,c;};
long n, m, i, dmin[nmax], a, b, c;
set <pair <long, long> > h;
pair <long, long> x;
vector <element> ma[nmax];
vector <element>::iterator it;
element el;
bool ok, fol[nmax];

void citire()
{
    scanf("%ld %ld",&n,&m);
    for (i=1;i<=m;i++)
    {
        scanf("%ld %ld %ld",&a,&b,&c);
        el.n=b; el.c=c;
        ma[a].push_back(el);
    }
}

void rezolvare()
{
    for (i=2;i<=n;i++)
        dmin[i]=inf;
    h.insert(make_pair(0,1));
    while (h.size())
    {
        x=*h.begin();    h.erase(h.begin());
		if (fol[x.second])
		{	ok=0;	break;	}
		fol[x.second]=1;
        for (it=ma[x.second].begin();it!=ma[x.second].end();it++)
            if (dmin[(*it).n]>dmin[x.second]+(*it).c)
            {
                h.erase(make_pair(dmin[(*it).n],(*it).n));
                dmin[(*it).n]=dmin[x.second]+(*it).c;
                h.insert(make_pair(dmin[(*it).n],(*it).n));
            }
    }
}


int main()
{
    freopen("bellmanford.in","r",stdin);
    freopen("bellmanford.out","w",stdout);
    citire();
	ok=1;
    rezolvare();
	if (ok==0)
		printf("Ciclu negativ!");
	else
		for (i=2;i<=n;i++)
			if (dmin[i]!=inf)
				printf("%ld ",dmin[i]);
			else
				printf("0 ");
    return 0;
}