Cod sursa(job #565830)

Utilizator alexandra_naeNae Alexandra Beatrice alexandra_nae Data 28 martie 2011 12:34:39
Problema Algoritmul lui Dijkstra Scor 90
Compilator cpp Status done
Runda Arhiva educationala Marime 1.35 kb
#include<stdio.h>
#include<queue>
#include<vector>
using namespace std;

const int N=50715;
const int INF=1000000000;

struct succesor 
{
	int nod,cost;
};

vector<succesor> a[N];
priority_queue<pair<int,int> > h;
int n,d[N];
bool s[N];
void afisare();
void init();
void citire();
int cost_vf_min();
void dijkstra(int x0);
void actualizare(int x);


int main()
{
	freopen("dijkstra.in","r",stdin);
	freopen("dijkstra.out","w",stdout);
	
	citire();
	init();
	dijkstra(1);
	afisare();
	
	return 0;
}

void citire()
{
	int m,i,x,y,c;
	scanf("%d%d",&n,&m);
	for(i=1;i<=m;i++)
	{
		scanf("%d%d%d",&x,&y,&c);
		a[x].push_back((succesor){y,c});
	}
}
	
void init()
{
	for(int i=0 ; i<=n ; i++)
		d[i] = INF;
}

int vf_cost_min()
{
	while(!h.empty())
	{
		if(!s[h.top().second])
			return h.top().second;
		h.pop();
	}
	return 0;
}

void dijkstra(int x0)
{
	int x;
	d[x0] = 0;
	h.push(make_pair(d[x0],x0));
	for(int i=1 ; i<n ; i++)
	{
		x = vf_cost_min();
		if(d[x] == INF)
			return;
		s[x] = true;
		actualizare(x);
	}
}

void afisare()
{
	int i;
	for(i=2;i<=n;i++)
		if(d[i] == INF)
			printf("0 ");
		else
			printf("%d ", d[i]);
}

	


void actualizare(int x)
{
	int c,y;
	for(size_t i=0 ; i<a[x].size() ; i++)
	{
		y = a[x][i].nod;
		c = a[x][i].cost;
		if(d[x] + c < d[y])
		{
			d[y] = d[x] + c;
			h.push(make_pair(-d[y],y));
		}
	}
}