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dijkstra.c
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dijkstra.c
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#include <stdio.h>
#include <stdlib.h>
#define inf 9999999
typedef struct listNode{
// Nodul cu care are muchie detinatorul listei
int node;
// Costul dintre detinatorul listei si node
int cost;
struct listNode *next;
} listNode;
typedef struct graph{
// Numarul de noduri ale grafului
int nodes;
// adj_heads[i] -> lista de adiacenta a nodului i
listNode **adj_heads;
} graph;
typedef struct heap{
int *arr;
int size;
}heap;
heap *createHeap(int n)
{
heap *new = malloc(sizeof(heap));
new->arr = calloc(n + 1, sizeof(int));
new->size = 0;
return new;
}
int getLeftChild(int index)
{
return 2 * index;
}
int getRightChild(int index)
{
return 2 * index + 1;
}
int getParent(int index)
{
return index / 2;
}
void swap(heap *h, int i, int j)
{
int temp = h->arr[i];
h->arr[i] = h->arr[j];
h->arr[j] = temp;
}
int hasLeftChild(heap *h, int index)
{
return getLeftChild(index) <= h->size;
}
int hasRightChild(heap *h, int index)
{
return getRightChild(index) <= h->size;
}
void heapifyUp(heap *h, int index, int d[], int poz[])
{
while(index > 1)
{
int parent = getParent(index);
if(d[h->arr[parent]] > d[h->arr[index]])
{
poz[h->arr[index]] = parent;
poz[h->arr[parent]] = index;
swap(h, parent, index);
index = parent;
}
else index = 1;
}
}
void heapifyDown(heap *h, int index, int d[], int poz[])
{
int f;
while(index <= h->size)
{
f = index;
if(hasLeftChild(h, index))
{
if(hasRightChild(h, index) &&
d[h->arr[getRightChild(index)]] < d[h->arr[getLeftChild(index)]])
f = getRightChild(index);
else f = getLeftChild(index);
}
else return;
if(d[h->arr[index]] > d[h->arr[f]]){
poz[h->arr[index]] = f;
poz[h->arr[f]] = index;
swap(h, index, f);
index = f;
}
else return;
}
}
void addEdge(graph *g, int v1, int v2, int cost)
{
listNode *new;
new = (listNode *) malloc(sizeof(listNode));
new->node = v2;
new->cost = cost;
new->next = g->adj_heads[v1];
g->adj_heads[v1] = new;
}
void freeList(listNode *list) {
listNode *it = list, *prev;
while (it != NULL) {
prev = it;
it = it->next;
free(prev);
}
}
void destroyGraph(graph *g)
{
for (int i = 0; i <= g->nodes; i++)
freeList(g->adj_heads[i]);
free(g->adj_heads);
free(g);
}
graph *createGraph(int nodes)
{
graph *g = (graph*) malloc(sizeof(graph));
g->nodes = nodes;
g->adj_heads = (listNode**) calloc(nodes + 1, sizeof(listNode*));
return g;
}
void dijkstra(graph *g, heap *h, int source, int d[], int poz[])
{
int *pred = calloc(g->nodes, sizeof(int));
for ( int i = 1; i <= g->nodes; ++i )
if(i != source) d[i] = inf, poz[i] = -1, pred[i] = 1;
poz[source] = 1;
h->arr[++h->size] = source;
while(h->size)
{
int min = h->arr[1];
swap(h, 1, h->size);
poz[h->arr[1]] = 1;
h->size--;
heapifyDown(h, 1, d ,poz);
listNode *it = g->adj_heads[min];
while (it)
{
if (d[it->node] > d[min] + it->cost)
{
d[it->node] = d[min] + it->cost;
pred[it->node] = min;
if (poz[it->node] != -1)
heapifyUp(h, poz[it->node], d, poz);
else
{
h->arr[++h->size] = it->node;
poz[h->arr[h->size]] = h->size;
heapifyUp(h, h->size, d, poz);
}
}
it = it->next;
}
}
for(int i = 2; i <= g->nodes; i++)
printf("%d ", pred[i]);
}
int main()
{
graph *g;
heap *h;
FILE *fin = fopen("dijkstra.in", "r");
FILE *fout = fopen("dijkstra.out", "w");
int N, M, v1, v2, cost, d[100001], q[100001];
fscanf(fin, "%d%d", &N, &M);
g = createGraph(N);
h = createHeap(N);
for(int i = 1; i <= N; i++)
d[i] = q[i] = 0;
for(int i = 1; i <= M; i++)
{
fscanf(fin, "%d%d%d", &v1, &v2, &cost);
addEdge(g, v1, v2, cost);
}
dijkstra(g, h, 1, d, q);
for(int i = 1; i <= N; i++)
fprintf(fout, "%d ", d[i] == inf ? -1 : d[i]);
fprintf(fout, "\n");
destroyGraph(g);
free(h->arr);
free(h);
fclose(fin);
fclose(fout);
}