int btree_delete_ex (PBTREE btree, int node_idx, long target_key) {
// target is just a package for the key value. the reference does not
// provide the address of the Elem instance to be deleted.
// first find the node contain the Elem instance with the given key
int parent_index_this = BTREE_INVALID_ELEMENT_IDX;
PBTREE_ELEMENT found;
int last_visted_node_idx;
if (node_idx == BTREE_INVALID_NODE_IDX)
node_idx = btree->root_node_idx;
last_visted_node_idx = node_idx;
found = btree_search_ex (btree, &last_visted_node_idx, target_key);
if (!found)
return 0;
if (is_leaf(btree, last_visted_node_idx) && key_count(btree, last_visted_node_idx) > btree_minimum_keys())
return vector_delete (btree, last_visted_node_idx, target_key);
else if (is_leaf(btree, last_visted_node_idx)) {
vector_delete (btree, last_visted_node_idx, target_key);
// loop invariant: if _node_ is not null_ptr, it points to a node
// that has lost an element and needs to import one from a sibling
// or merge with a sibling and import one from its parent.
// after an iteration of the loop, _node_ may become null or
// it may point to its parent if an element was imported from the
// parent and this caused the parent to fall below the minimum
// element count.
while (BTREE_IS_VALID_NODE_IDX(last_visted_node_idx)) {
int right, left;
// NOTE: the "this" pointer may no longer be valid after the first
// iteration of this loop!!!
if (last_visted_node_idx == find_root(btree) && is_leaf(btree, last_visted_node_idx))
break;
if (last_visted_node_idx == find_root(btree) && !is_leaf(btree, last_visted_node_idx)) // sanity check
return 0;
// is an extra element available from the right sibling (if any)
right = right_sibling(btree, last_visted_node_idx, &parent_index_this);
if (BTREE_IS_VALID_NODE_IDX(right) && key_count(btree, right) > btree_minimum_keys())
last_visted_node_idx = rotate_from_right(btree, last_visted_node_idx, parent_index_this);
else {
// is an extra element available from the left sibling (if any)
left = left_sibling(btree, last_visted_node_idx, &parent_index_this);
if (BTREE_IS_VALID_NODE_IDX(left) && key_count(btree, left) > btree_minimum_keys())
last_visted_node_idx = rotate_from_left(btree, last_visted_node_idx, parent_index_this);
else if (BTREE_IS_VALID_NODE_IDX(right))
last_visted_node_idx = merge_right(btree, last_visted_node_idx, parent_index_this);
else if (BTREE_IS_VALID_NODE_IDX(left))
last_visted_node_idx = merge_left(btree, last_visted_node_idx, parent_index_this);
}
}
}
else {
PBTREE_ELEMENT smallest_in_subtree = smallest_key_in_subtree(btree, found->subtree_node_idx);
found->key = smallest_in_subtree->key;
found->data_entry_idx = smallest_in_subtree->data_entry_idx;
btree_delete_ex (btree, found->subtree_node_idx, smallest_in_subtree->key);
}
return 1;
}
int can_move_right(board *b)
{
board *tmp;
tmp = dup_board(b);
shift_right(tmp);
merge_right(tmp);
shift_right(tmp);
if (cmp_board(b, tmp)) {
free(tmp);
return 0;
} else {
free(tmp);
return 1;
}
}
void motor_control(void) //Different scenerios that will light up the LEDs in a certain way,
//and the motor reactions to the scenarios.
{
if (!SeeLine.b.Left&&!SeeLine.b.CntLeft&&SeeLine.b.Center&&!SeeLine.b.CntRight&&!SeeLine.b.Right) straight_fwd(); //00100
else if (SeeLine.b.Left&&!SeeLine.b.CntLeft&&!SeeLine.b.Center&&!SeeLine.b.CntRight&&!SeeLine.b.Right) spin_left(); //10000
else if (SeeLine.b.Left&&SeeLine.b.CntLeft&&!SeeLine.b.Center&&!SeeLine.b.CntRight&&!SeeLine.b.Right) spin_left(); //11000
else if (!SeeLine.b.Left&&SeeLine.b.CntLeft&&!SeeLine.b.Center&&!SeeLine.b.CntRight&&!SeeLine.b.Right) turn_left(); //01000
else if (!SeeLine.b.Left&&SeeLine.b.CntLeft&&SeeLine.b.Center&&!SeeLine.b.CntRight&&!SeeLine.b.Right) turn_left(); //01100
else if (!SeeLine.b.Left&&!SeeLine.b.CntLeft&&!SeeLine.b.Center&&SeeLine.b.CntRight&&!SeeLine.b.Right) turn_right();//00010
else if (!SeeLine.b.Left&&!SeeLine.b.CntLeft&&SeeLine.b.Center&&SeeLine.b.CntRight&&!SeeLine.b.Right) turn_right(); //00110
else if (!SeeLine.b.Left&&!SeeLine.b.CntLeft&&!SeeLine.b.Center&&!SeeLine.b.CntRight&&SeeLine.b.Right) spin_right();//00001
else if (!SeeLine.b.Left&&!SeeLine.b.CntLeft&&!SeeLine.b.Center&&SeeLine.b.CntRight&&SeeLine.b.Right) spin_right(); //00011
else if ( (SeeLine.B ) == 0b00000u) Check_Gaps(); //00000 //all LEDs OFF
else if (!SeeLine.b.Left&&!SeeLine.b.CntLeft&&SeeLine.b.Center&&SeeLine.b.CntRight&&SeeLine.b.Right) right_right_angle_turns(); //00111
else if (SeeLine.b.Left&&SeeLine.b.CntLeft&&SeeLine.b.Center&&!SeeLine.b.CntRight&&!SeeLine.b.Right) left_right_angle_turns(); //11100
else if (!SeeLine.b.Left&&!SeeLine.b.CntLeft&&SeeLine.b.Center&&!SeeLine.b.CntRight&&SeeLine.b.Right) sharp_right_turns(); //00101
else if (SeeLine.b.Left&&!SeeLine.b.CntLeft&&SeeLine.b.Center&&!SeeLine.b.CntRight&&!SeeLine.b.Right) sharp_left_turns(); //10100
else if (SeeLine.b.Left&&!SeeLine.b.CntLeft&&!SeeLine.b.Center&&SeeLine.b.CntRight&&!SeeLine.b.Right) merge_right(); //10010
else if (!SeeLine.b.Left&&SeeLine.b.CntLeft&&!SeeLine.b.Center&&!SeeLine.b.CntRight&&SeeLine.b.Right) merge_left(); //01001
else if (SeeLine.b.Left&&SeeLine.b.CntLeft&&!SeeLine.b.Center&&SeeLine.b.CntRight&&!SeeLine.b.Right) merge_right(); //11010
else if (!SeeLine.b.Left&&SeeLine.b.CntLeft&&!SeeLine.b.Center&&SeeLine.b.CntRight&&SeeLine.b.Right) merge_left(); //01011
else if (SeeLine.b.Left&&SeeLine.b.CntLeft&&SeeLine.b.Center&&SeeLine.b.CntRight&&SeeLine.b.Right) final_ends(); //11111 //all LEDs ON
}
void play_game()
{
board *b = &grid;
do {
switch (os_wait_for_key()) {
case ESC_KEY:
return;
case UP_KEY:
if (can_move_up(b)) {
shift_up(b);
merge_up(b);
shift_up(b);
add_big_int(&score, &merge_score);
break;
} else {
continue;
}
case DOWN_KEY:
if (can_move_down(b)) {
shift_down(b);
merge_down(b);
shift_down(b);
add_big_int(&score, &merge_score);
break;
} else {
continue;
}
case LEFT_KEY:
if (can_move_left(b)) {
shift_left(b);
merge_left(b);
shift_left(b);
add_big_int(&score, &merge_score);
break;
} else {
continue;
}
case RIGHT_KEY:
if (can_move_right(b)) {
shift_right(b);
merge_right(b);
shift_right(b);
add_big_int(&score, &merge_score);
break;
} else {
continue;
}
default:
continue;
}
add_tile(b);
display_board(b);
} while (!game_is_lost());
}
