Cod sursa(job #673468)

Utilizator ukiandreaAndreea Lucau ukiandrea Data 4 februarie 2012 15:33:27
Problema Algoritmul lui Dijkstra Scor 0
Compilator cpp Status done
Runda Arhiva educationala Marime 3.19 kb
#include <stdio.h>
#include <stdlib.h>

#include <queue>

#define INF 1000000

struct djikstra_node {
	djikstra_node(int v)
	{
		value = v;
		distance = INF;
	}

	bool operator<(const djikstra_node &n) const
	{
		return distance < n.distance;
	}

	int value;
	int distance;
};

class djikstra_compare
{
public:	
	bool operator() (const djikstra_node& lhs, const djikstra_node& rhs) const
	{
		return (lhs.distance > rhs.distance);
	}
};

struct node {
	int value;
	int weight;
	struct node *next;
};

struct list {
	node *head;
};

list* create_list()
{
	list *l = (list*)calloc(1, sizeof(list));
	l->head = NULL;
	return l;
}

void insert_list(list* l, int value, int weight)
{
	if (l->head == NULL) {
		l->head = (node*)calloc(1, sizeof(node));
		l->head->value = value;
		l->head->weight = weight;
		return;
	}

	node *p = l->head;
	while (p->next != NULL)
		p = p->next;

	node *n = (node*)calloc(1, sizeof(node));
	n->value = value;
	n->weight = weight;
	p->next = n;
}

void destroy_list(list **l)
{
	while ((*l)->head != NULL) {
		node *p = (*l)->head;
		(*l)->head = (*l)->head->next;

		free(p);
	}
}

enum colors {
	WHITE = 0,
	GRAY,
	BLACK
};

struct graph {
	int n;
	list **adj;
	int *colors;
	int *parents;
	djikstra_node *nodes;
};

graph* create_graph(int size)
{
	graph *g = (graph*)calloc(1, sizeof(graph));
	g->n = size;
	g->adj = (list**)calloc(size, sizeof(list*));
	g->colors = (int*)calloc(size, sizeof(int));
	g->parents = (int*)calloc(size, sizeof(int));
	g->nodes = (djikstra_node*)calloc(size, sizeof(djikstra_node));

	for (int i = 0; i < size; i++) 
		g->nodes[i] = djikstra_node(i);

	return g;
}

void add_graph_edge(graph *g, int v1, int v2, int w)
{
	if (g->adj[v1] == NULL) 
		g->adj[v1] = create_list();

	insert_list(g->adj[v1], v2, w);
}

void clear_graph_value(graph *g)
{
	for (int i = 0; i < g->n; i++) {
		g->colors[i] = WHITE;
		g->parents[i] =  -1;
	}
}

void destroy_graph(graph **g)
{
	for (int i = 0; i < (*g)->n; i++) {
		if ((*g)->adj[i])
			destroy_list(&((*g)->adj[i]));
	}

	free((*g)->adj);
	free((*g)->colors);
	free((*g)->parents);
	free(*g);
}

void djikstra(graph *g)
{
	std::priority_queue<djikstra_node, std::vector<djikstra_node>, djikstra_compare> q;
	for (int i = 0; i < g->n; i++)
		q.push(g->nodes[i]);

	while (q.size()) {
		djikstra_node n = q.top(); 
		if (n.distance == INF)
			break;

		q.pop();
		g->colors[n.value] = GRAY;

		/*
		node *x = (g->adj[n.value]) ? g->adj[n.value]->head : NULL;
		while (x) {
			if (g->colors[x->value] == WHITE) {
				int d = g->nodes[n.value].distance + x->weight;
				if (d < g->nodes[x->value].distance) {
					g->nodes[x->value].distance = d;
					q.push(g->nodes[x->value]);
				}
			}

			x = x->next;
		}
		*/
	}
}

int main()
{
	int v, e;
	graph * g = NULL;

	freopen("djikstra.in", "r", stdin);
	freopen("djikstra.out", "w", stdout);

	scanf("%d %d\n", &v, &e);
	g = create_graph(v);

	for (int i = 0; i < e; i++) {
		int v1, v2, w;

		scanf("%d %d %d\n", &v1, &v2, &w);
		add_graph_edge(g, v1 - 1, v2 - 1, w);
	}

	g->nodes[0].distance = 0;
	clear_graph_value(g);

	djikstra(g);

	for (int i = 1; i < g->n; i++) 
		printf("%d ", g->nodes[i].distance == INF ? 0 : g->nodes[i].distance);
	printf("\n");

	destroy_graph(&g);

	return 0;
}