Language: C

#include<stdio.h>
#include<stdlib.h>
#include<limits.h>
struct node {
        int id;
        int weight;
        struct node *next;
};
struct node **list;
int *dist, *prev, *heap, *heap_index, heapsize;
void Insert(int, int, int);
void downheap(int);
void upheap(int);
void PQ_Init(int);
void DijkstraPQ(int, int);
main()
{
        int i, n, e, r, s, t, d;
        scanf("%d%d%d", &n, &e, &r);
        list = (struct node**)malloc(sizeof(struct node*) * n);
        for (i = 0; i < n; i++) {
                dist = (int*)malloc(sizeof(int) * n);
                prev = (int*)malloc(sizeof(int) * n);
                list[i] = NULL;
        }
        for (i = 0; i < e; i++) {
                        scanf("%d%d%d", &s, &t, &d);
                        Insert(s, t, d);
        }
                Disp(n);
        DijkstraPQ(r, n);
        for (i = 0; i < n; i++) {
                        struct node *p, *q;
                        if (dist[i] != INT_MAX) {
                                printf("%d\n", dist[i]);
                        } else {
                                printf("INF\n");
                        }
                        if (list[i] != NULL) {
                                for (q = list[i], p = q->next; p != NULL; q = p, p = p->next) {
                                        q->next = p->next;
                                        free(p);
                                }
                                free(list[i]);
                        }
        }
        free(list);
        free(dist);
        free(prev);
        free(heap);
        free(heap_index);
}
void Insert(int a, int b, int weight)
{
        struct node *p = (struct node*)malloc(sizeof(struct node));
        p->id = b;
        p->weight = weight;
        p->next = list[a];
        list[a] = p;
}
void downheap(int k)
{
        int j, v = heap[k];
        while (k < heapsize / 2) {
                j = 2 * k + 1;
                if (j < heapsize - 1 && dist[heap[j]] > dist[heap[j + 1]]) j++;
                if (dist[v] <= dist[heap[j]]) break;
                heap[k] = heap[j];
                heap_index[heap[j]] = k;
                k = j;
        }
        heap[k] = v;
        heap_index[v] = k;
}
void upheap(int j)
{
        int k, v = heap[j];
        while (j > 0) {
                k = (j + 1) / 2 - 1;
                if (dist[v] >= dist[heap[k]]) break;
                heap[j] = heap[k];
                heap_index[heap[k]] = j;
                j = k;
        }
        heap[j] = v;
        heap_index[v] = j;
}
void PQ_Init(int size)
{
        int i;
        heapsize = size;
        heap = (int*)malloc(sizeof(int) * size);
        heap_index = (int*)malloc(sizeof(int) * size);
        for (i = 0; i < size; i++) {
                heap[i] = i;
                heap_index[i] = i;
        }
        for (i = size / 2 - 1; i >= 0; i--) {
                downheap(i);
        }
}
void DijkstraPQ(int p, int size)
{
        int i;
        for (i = 0; i < size; i++) {
                dist[i] = INT_MAX;
                prev[i] = -1;
        }
        dist[p] = 0;
        PQ_Init(size);
        while (heapsize > 0) {
                struct node *n;
                int u = heap[0];
                heap[0] = heap[heapsize - 1];
                heap_index[heap[size - 1]] = 0;
                heapsize--;
                downheap(0);
                for (n = list[u]; n != NULL; n = n->next) {
                        long int w = n->weight, newlen = dist[u] + w;
                        if (newlen < dist[n->id]) {
                                                        dist[n->id] = newlen;
                                                        prev[n->id] = u;
                                                        upheap(heap_index[n->id]);
                        }
                }
        }
}


Compiler output:
main.c:16:1: error: return type defaults to 'int' [-Wimplicit-int]
   16 | main()
      | ^~~~
main.c: In function 'main':
main.c:30:17: error: implicit declaration of function 'Disp' [-Wimplicit-function-declaration]
   30 |                 Disp(n);
      |                 ^~~~