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#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <stdint.h>
#include <unistd.h>
#include <termios.h>
#include <time.h>
typedef struct
{
uint16_t bm;
char icon;
} Player;
typedef struct
{
Player max_player;
Player min_player;
} Board;
const uint16_t wincombs[8] = {
0b111000000, 0b000111000, 0b000000111, 0b100100100,
0b010010010, 0b001001001, 0b100010001, 0b001010100};
void render(Board *board);
uint8_t askmove(Board *board, char *player);
uint8_t evaluate(Board *board);
void checkposition(Board *board);
uint8_t minimax_alpha_beta(Board *board, bool ismax, uint8_t alpha, uint8_t beta);
uint8_t best_move(Board *board, bool ismax);
unsigned int random_number(unsigned int limit);
int main(void)
{
Board activeBoard = {
.max_player = {.bm = 0b000000000, .icon = 'x'},
.min_player = {.bm = 0b000000000, .icon = 'o'}
};
uint8_t user_move;
uint8_t computer_move;
time_t time = clock();
computer_move = best_move(&activeBoard, false);
time = clock() - time;
double exec_time = ((double) time) / CLOCKS_PER_SEC;
printf("bestmove function took %f seconds\n", exec_time);
int scanvar;
scanf("%d", &scanvar);
while (true) {
checkposition(&activeBoard);
render(&activeBoard);
user_move = askmove(&activeBoard, &activeBoard.max_player.icon);
activeBoard.max_player.bm ^= 0b100000000 >> user_move;
checkposition(&activeBoard);
computer_move = best_move(&activeBoard, false);
activeBoard.min_player.bm ^= 0b100000000 >> computer_move;
}
return 0;
}
void render(Board *board)
{
uint8_t i;
uint16_t wincomb;
uint16_t color_bm = 0b000000000;
for (i = 0; i < 8; i++) {
wincomb = wincombs[i];
if ((wincomb & board->max_player.bm) == wincomb || (wincomb & board->min_player.bm) == wincomb) {
color_bm |= wincomb;
}
}
printf(
"\n %s%c\x1b[0m │ %s%c\x1b[0m │ %s%c\x1b[0m \n───┼───┼───\n %s%c\x1b[0m │ %s%c\x1b[0m │ %s%c\x1b[0m \n───┼───┼───\n %s%c\x1b[0m │ %s%c\x1b[0m │ %s%c\x1b[0m \n",
(0b100000000 & color_bm) ? "\x1b[7m" : "",
(0b100000000 & board->max_player.bm) ? board->max_player.icon : (0b100000000 & board->min_player.bm) ? board->min_player.icon : '1',
(0b010000000 & color_bm) ? "\x1b[7m" : "",
(0b010000000 & board->max_player.bm) ? board->max_player.icon : (0b010000000 & board->min_player.bm) ? board->min_player.icon : '2',
(0b001000000 & color_bm) ? "\x1b[7m" : "",
(0b001000000 & board->max_player.bm) ? board->max_player.icon : (0b001000000 & board->min_player.bm) ? board->min_player.icon : '3',
(0b000100000 & color_bm) ? "\x1b[7m" : "",
(0b000100000 & board->max_player.bm) ? board->max_player.icon : (0b000100000 & board->min_player.bm) ? board->min_player.icon : '4',
(0b000010000 & color_bm) ? "\x1b[7m" : "",
(0b000010000 & board->max_player.bm) ? board->max_player.icon : (0b000010000 & board->min_player.bm) ? board->min_player.icon : '5',
(0b000001000 & color_bm) ? "\x1b[7m" : "",
(0b000001000 & board->max_player.bm) ? board->max_player.icon : (0b000001000 & board->min_player.bm) ? board->min_player.icon : '6',
(0b000000100 & color_bm) ? "\x1b[7m" : "",
(0b000000100 & board->max_player.bm) ? board->max_player.icon : (0b000000100 & board->min_player.bm) ? board->min_player.icon : '7',
(0b000000010 & color_bm) ? "\x1b[7m" : "",
(0b000000010 & board->max_player.bm) ? board->max_player.icon : (0b000000010 & board->min_player.bm) ? board->min_player.icon : '8',
(0b000000001 & color_bm) ? "\x1b[7m" : "",
(0b000000001 & board->max_player.bm) ? board->max_player.icon : (0b000000001 & board->min_player.bm) ? board->min_player.icon : '9'
);
}
uint8_t askmove(Board *board, char *player)
{
static struct termios term_settings;
char c;
uint16_t empty_cells = ~(board->max_player.bm | board->min_player.bm) & 0b111111111;
uint8_t i;
uint16_t cell_bm;
/* changing term settings for special input */
tcgetattr(STDIN_FILENO, &term_settings);
term_settings.c_lflag ^= ICANON | ECHO;
tcsetattr(STDIN_FILENO, TCSANOW, &term_settings);
printf("\nWhere do you want to place your %c?\n", *player);
while ((c = getc(stdin)) != EOF) {
for (i = 0; i < 9; i++) {
cell_bm = 0b100000000 >> i;
if (empty_cells & cell_bm && c - '1' == i) {
/* restoring old term settings */
term_settings.c_lflag ^= ICANON | ECHO;
tcsetattr(STDIN_FILENO, TCSANOW, &term_settings);
return i;
}
}
}
exit(0);
}
uint8_t evaluate(Board *board)
{
uint8_t i;
uint16_t wincomb;
/*
0 -> position not terminal
1 reserved for -infinity
2 -> player2 wins
3 -> draw = noone wins
4 -> player1 wins
5 reserved for infinity
*/
for (i = 0; i < 8; i++) {
wincomb = wincombs[i];
if ((wincomb & board->max_player.bm) == wincomb) {
return 4;
}
if ((wincomb & board->min_player.bm) == wincomb) {
return 2;
}
}
if ((board->max_player.bm | board->min_player.bm) == 0b111111111) {
return 3;
}
return 0;
}
void checkposition(Board *board)
{
uint8_t eval = evaluate(board);
uint16_t color_bm;
uint8_t i;
uint16_t wincomb;
if (eval) {
render(board);
if (eval == 3) {
printf("\nDRAW\n\n");
} else if (eval == 4) {
printf("\n%c won the game!\n\n", board->max_player.icon);
} else if (eval == 2) {
printf("\n%c won the game!\n\n", board->min_player.icon);
}
exit(0);
}
}
uint8_t minimax_alpha_beta(Board *board, bool ismax, unsigned char alpha, unsigned char beta)
{
uint16_t empty_cells_bm = ~(board->max_player.bm | board->min_player.bm) & 0b111111111;
uint8_t eval = evaluate(board);
uint8_t bestvalue;
uint8_t i;
uint16_t cell_bm;
uint8_t minimax_value;
if (eval) {
return eval;
}
if (ismax) {
bestvalue = 1;
for (i = 0; i < 9; i++) {
cell_bm = 0b100000000 >> i;
if (cell_bm & empty_cells_bm) {
board->max_player.bm ^= cell_bm;
minimax_value = minimax_alpha_beta(board, false, alpha, beta);
board->max_player.bm ^= cell_bm;
if (minimax_value > bestvalue) {
bestvalue = minimax_value;
if (bestvalue > alpha) {
alpha = bestvalue;
}
if (alpha >= beta) {
break;
}
}
}
}
} else {
bestvalue = 5;
for (i = 0; i < 9; i++) {
cell_bm = 0b100000000 >> i;
if (cell_bm & empty_cells_bm) {
board->min_player.bm ^= cell_bm;
minimax_value = minimax_alpha_beta(board, true, alpha, beta);
board->min_player.bm ^= cell_bm;
if (minimax_value < bestvalue) {
bestvalue = minimax_value;
if (bestvalue < beta) {
beta = bestvalue;
}
if (alpha >= beta) {
break;
}
}
}
}
}
return bestvalue;
}
uint8_t best_move(Board *board, bool ismax)
{
uint8_t bestvalue;
uint8_t i;
uint16_t cell_bm;
uint16_t empty_cells_bm = ~(board->max_player.bm | board->min_player.bm) & 0b111111111;
uint8_t minimax_value;
uint8_t cell_values[9];
uint8_t ctr = 0;
uint8_t choice;
if (ismax) {
bestvalue = 1;
for (i = 0; i < 9; i++) {
cell_bm = 0b100000000 >> i;
if (cell_bm & empty_cells_bm) {
board->max_player.bm ^= cell_bm;
minimax_value = minimax_alpha_beta(board, !ismax, 1, 5);
board->max_player.bm ^= cell_bm;
if (minimax_value == bestvalue) {
cell_values[i] = minimax_value;
++ctr;
} else if (minimax_value > bestvalue) {
bestvalue = minimax_value;
cell_values[i] = minimax_value;
ctr = 1;
}
}
}
} else {
bestvalue = 5;
for (i = 0; i < 9; i++) {
cell_bm = 0b100000000 >> i;
if (cell_bm & empty_cells_bm) {
board->min_player.bm ^= cell_bm;
minimax_value = minimax_alpha_beta(board, !ismax, 1, 5);
board->min_player.bm ^= cell_bm;
if (minimax_value == bestvalue) {
cell_values[i] = minimax_value;
++ctr;
} else if (minimax_value < bestvalue) {
bestvalue = minimax_value;
cell_values[i] = minimax_value;
ctr = 1;
}
}
}
}
choice = random_number(ctr);
for (i = 0; i < 9; i++) {
if (cell_values[i] == bestvalue) {
if (!choice) {
return i;
} else {
--choice;
}
}
}
return 0b11111111;
}
unsigned int random_number(unsigned int limit)
{
srand(time(0));
return rand() % limit;
}
/* python exectime > 0.066766 */
/* C exectime > 0.003077 */
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