12-tower-of-hanoi/toh_solver.c

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4.1 KiB
C

/*----------------------------------------------------------
* HTBLA-Leonding / Class: 2IHIF
* ---------------------------------------------------------
* Exercise Number: 09
* Title: Tower of Hanoi Disk ADT implementation
* Author: Marc Tismonar
* ----------------------------------------------------------
* Description:
* Implementation of toh_board.h.
* ----------------------------------------------------------
*/
/* Includes, definitions and instanciations */
#include "toh_board.h"
#include "config.h"
#include "toh_disk.h"
#include "toh_board.h"
#include "toh_visualizer.h"
/* ========================================================= */
/* Private functions */
static int moveCount = 0;
/**
* Moves a single disk from the top of the 'source' rod to the 'target' rod.
* The move shall only be performed if it is allowed.
*
* @param source The rod from which the disk shall be moved.
* @param target The rod to which the disk shall be moved.
* @return True if the move was successful and according to the rules, false otherwise.
*/
static bool ts_move_disk(RodName source, RodName target) {
TohBoard board = tb_get_board();
if (!tb_is_valid(board)) {
return false;
}
Disk disk = tb_pop_disk(board, source);
if (!td_is_valid(disk)) {
return false;
}
bool success = tb_push_disk(tb_get_board(), target, disk);
if (success) {
moveCount++;
toh_visualize(tb_get_board(), moveCount);
}
return success;
}
/**
* Moves a stack of disks of the given size form the 'source' rod to the 'target' rod
* using the 'intermediate' rod as intermediate disk buffer.
* The move shall only be performed if it is valid. The move is valid, if each
* move of affected disks is allowed.
*
* @param size The size of the disk stack to move.
* @param source The rod from which the disks shall be moved.
* @param intermediate The rod that serves as intermediate buffer for the disks.
* @param target The rod to which the disks shall be moved.
* @return True if the move was successful and according to the rules, false otherwise.
*/
static bool ts_move_stack(unsigned short size, RodName source, RodName intermediate, RodName target) {
if (size == 1) {
return ts_move_disk(source, target);
}
if (!ts_move_stack(size - 1, source, target, intermediate)) {
return false;
}
if (!ts_move_disk(source, target)) {
return false;
}
return ts_move_stack(size - 1, intermediate, source, target);
}
static unsigned short ts_get_used_disks(RodName rod) {
TohBoard board = tb_get_board();
if (!tb_is_valid(board)) {
return 0;
}
unsigned short count = 0;
for (unsigned short i = 0; i < MAX_DISKS; i++) {
Disk disk = tb_get_disk(board, rod, i);
if (td_is_valid(disk)) {
count++;
}
}
return count;
}
/* ========================================================= */
/* Public functions */
/**
* Initials a 'Tower of Hanoi' board with the given number of disks.
* To initialize the board, all reqired disks are placed on the left rod
* in ascending order of their size, the smallest disk at the top.
* The middle and right rod are empty.
*
* All disks are initialized accordingly.
*
* @param disk_count The number of disks to use. Must be less than 'MAX_DISKS'.
*/
void ts_init(unsigned short disk_count) {
if(disk_count < 1 || disk_count > MAX_DISKS) {
return;
}
TohBoard board = tb_get_board();
tb_clear_board(board);
for (unsigned short i = disk_count; i > 0; i--) {
Disk disk = td_get_disk(i);
tb_push_disk(board, LEFT, disk);
}
moveCount = 0;
toh_init_visualizer(disk_count);
}
/**
* Solves the puzzle by moving all disks from the left rod to the right rod.
* In fact, this is the only function needed to 'play' the game after the
* board was initialized.
*
*/
void ts_solve() {
TohBoard board = tb_get_board();
if (!tb_is_valid(board)) {
return;
}
ts_move_stack(ts_get_used_disks(LEFT), LEFT, MIDDLE, RIGHT);
}