Cod sursa(job #723580)

Utilizator hunter_ionutzzzFarcas Ionut hunter_ionutzzz Data 25 martie 2012 17:05:00
Problema Algoritmul lui Dijkstra Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.66 kb
#include<fstream>
using namespace std;
ifstream fin("dijkstra.in");
ofstream fout("dijkstra.out");
#define lung 50001
#define inf 1 << 30
struct nod{int val,cost; 
		   nod *next;
};
int h[lung],d[lung],k,poz[lung],n,m,i;
nod *q,*v[lung];
inline void upheap(int x)
{int tata;
	while (x > 1)
	{   tata = x >> 1;
	    if (d[h[tata]] > d[h[x]])
		{   poz[h[tata]] = x;
		    poz[h[x]] = tata;
		    h[x] = h[x] + h[tata] - (h[tata] = h[x]);
			x= tata;
		}
		else
			x = 1;
	}
}
inline void downheap(int x)
{int fiu; 
	while (x <= k)
	{   fiu = x;
	    if ((x << 1) <= k)
		{   fiu = x << 1;
		    if (fiu+1 <= k)
				if (d[h[fiu+1]] < d[h[fiu]])
					++fiu;
		}
		else
			break;
		if (d[h[x]] > d[h[fiu]])
		{   poz[h[x]] = fiu;
		    poz[h[fiu]] = x;
			h[fiu] = h[fiu] + h[x] - (h[x] = h[fiu]);
			x = fiu;
		}
		else
			break;
	}
}
inline void dijkstra()
{int minim;
    for (i=2;i<=n;++i)
		d[i] = inf;
	h[1] = poz[1] = 1;
    ++k;
	while (k)
	{   minim = h[1];
	    h[1] = h[1] + h[k] - (h[k] = h[1]);
	    poz[h[1]] = 1;
		--k;
		downheap(1);
		q = v[minim];
		while (q)
		{   if (d[q->val] > d[minim] + q->cost)
		    {   d[q->val] = d[minim] + q->cost;
				if (poz[q->val])
					upheap(poz[q->val]);
				else
				{   h[++k] = q->val;
				    poz[h[k]] = k;
					upheap(k);
				}
			}
			q = q -> next;
		}
	}
}
int main()
{int a,c,b;
    fin >> n >> m;
    for (i=1;i<=m;++i)
	{   fin >> a >> b >> c;
	    q = new nod;
		q -> val = b;
		q -> next = v[a];
		q -> cost = c;
		v[a] = q;
	}
	dijkstra();
	for (i=2;i<=n;++i)
		if (d[i]!=inf)
			fout << d[i] << " ";
		else
			fout << "0 ";
	return 0;
}