void
push(struct EACH item)
{
int cld, pt;
++count;
queue[count-1] = item;
up_heapify(count-1);
}
void
Astar(char *start_str, int start_pos)
{
int i, th, hvalue, curp, nxtp;
char nxt[STR_LEN+1];
struct EACH cur, tmp;
strcpy(queue[0].str, start_str);
queue[0].pos = start_pos;
queue[0].value = hash_func(start_str);
count = 1;
mark[queue[0].value] = 1; /* open list */
g[queue[0].value] = 0;
h[queue[0].value] = estimate(start_str);
pre[queue[0].value] = -1;
dir[queue[0].value] = -1;
idx[queue[0].value] = 0;
while(count != 0) {
cur = pop();
if(cur.value == target) {
output(target);
printf("\n");
return;
}
mark[cur.value] = 2; /* add to closed-list */
curp = cur.pos;
for(i=0; i<4; i++) {
if(movable[curp][i]) {
nxtp = curp + pos[i];
strcpy(nxt, cur.str);
nxt[curp] = nxt[nxtp];
nxt[nxtp] = '0';
hvalue = hash_func(nxt);
if(mark[hvalue]==1 && g[hvalue]>(g[cur.value]+1)) { /* update */
g[hvalue] = g[cur.value]+1;
pre[hvalue] = cur.value;
dir[hvalue] = i;
up_heapify(idx[hvalue]);
} else if(mark[hvalue]==0) { /* add to open-list */
strcpy(tmp.str, nxt);
tmp.pos = nxtp;
tmp.value = hvalue;
mark[hvalue] = 1;
g[hvalue] = g[cur.value]+1;
h[hvalue] = estimate(nxt);
pre[hvalue] = cur.value;
dir[hvalue] = i;
idx[hvalue] = count;
push(tmp);
}
}
}
}
printf("unsolvable\n");
}
void up_heapify(int u){
int v = parent(u);
if(v != -1 && D[H[u]] < D[H[v]]){ // u is not the root of the heap
int tmp = H[u];
H[u] = H[v];
pos[H[v]] = u; // update the position of node H[v] in the Heap
H[v] = tmp;
pos[tmp] = v; // update the position of node tmp in the Heap
up_heapify(v);
}
}
void decrease_key(int u, int k){
D[u] = k;
up_heapify(pos[u]);
}
