/*
Teleport a piece to random location. If the piece is rotatable,
rotate the piece in random direction
*/
void Piece::teleportRandom()
{
pos.row = rand() % 9;
pos.col = rand() % 9;
int num_rot = rand() % 4;
if (can_rotate())
do { rotate_c(); } while (num_rot-- > 0);
}
pair *map_set(map *m, void *key, void *value) {
map_node *y, *z; /* Top node to update balance factor, and parent. */
map_node *p, *q; /* Iterator, and parent. */
map_node *n; /* Newly inserted node. */
map_node *w; /* New root of rebalanced subtree. */
unsigned char dir = 0; /* Direction to descend. */
unsigned char ds[MAX_HEIGHT]; /* Cached comparison results. */
int i = 0; /* Number of cached results. */
z = (map_node*)&m->x;
y = m->x;
for (q = z, p = y; p != NULL; q = p, p = p->children[dir]) {
int c = m->_cmp(key, p->x->a);
if (c == 0)
return p->x;
if (p->balance != 0) {
z = q;
y = p;
i = 0;
}
ds[i++] = dir = c > 0;
}
n = q->children[dir] = malloc(sizeof(map_node));
if (n == NULL)
return NULL;
m->size++;
n->x = create_pair(key, value);
n->left = n->right = NULL;
n->balance = 0;
if (y == NULL)
return n->x;
for (p = y, i = 0; p != n; p = p->children[ds[i]], i++) {
if (ds[i] == 0)
p->balance--;
else
p->balance++;
}
if (y->balance == -2) {
w = (y->left->balance == -1) ? rotate_c(y->left, y) : rotate_a(y->left, y);
} else if (y->balance == +2) {
w = (y->right->balance == +1) ? rotate_d(y->right, y) : rotate_b(y->right, y);
} else
return n->x;
z->children[y != z->left] = w;
return n->x;
}