#include #include #include #include #include "input.h" #define INPUT "input/04.txt" #define BOARD_COUNT 100 #define BOARD_SIZE 5 #define MAX_DRAW 500 typedef struct { long board[BOARD_SIZE][BOARD_SIZE]; bool board_marks[BOARD_SIZE][BOARD_SIZE]; } t_board; bool board_is_winning(t_board* board) { for(int i = 0; i < BOARD_SIZE; i++) { bool winning_i = true; bool winning_j = true; for(int j = 0; j < BOARD_SIZE; j++) { winning_i &= board->board_marks[i][j]; winning_j &= board->board_marks[j][i]; } if(winning_i || winning_j) return true; } return false; } bool board_mark(t_board* board, long draw) { for(int i = 0; i < BOARD_SIZE; i++) { for(int j = 0; j < BOARD_SIZE; j++) { if(board->board[i][j] == draw) board->board_marks[i][j] = true; } } return board_is_winning(board); } void board_init(t_board* board) { for(int i = 0; i < BOARD_SIZE; i++) { for(int j = 0; j < BOARD_SIZE; j++) { board->board[i][j] = 0; board->board_marks[i][j] = false; } } } void board_read(t_board* board_list, struct input_str* input) { for(int i = 0; i < BOARD_COUNT; i++) { board_init(&(board_list[i])); // read each line of the board for(int j = 0; j < BOARD_SIZE; j++) { // + 2 is for first line and empty line at start of board int line_index = i * (BOARD_SIZE + 1) + j + 2; char* line = input->lines[line_index]; char* start = line; char* end = NULL; // read each int for(int k = 0; k < BOARD_SIZE; k++) { board_list[i].board[j][k] = strtol(start, &end, 0); start = end; } } } } size_t draw_read(long* draw_list, struct input_str* input) { size_t i = 0; char *start = input->lines[0]; char *end = start; while(i < MAX_DRAW && *end != '\n') { draw_list[i] = strtol(start, &end, 0); start = end + 1; i++; } if(i == MAX_DRAW && *end != '\n') err(1, "draw list was truncated"); return i; } long board_unmarked_sum(t_board* board) { long sum = 0; for(int i = 0; i < BOARD_SIZE; i++) { for(int j = 0; j < BOARD_SIZE; j++) { if(!(board->board_marks)[i][j]) sum += (board->board)[i][j]; } } return sum; } void part1(struct input_str* input) { t_board board_list[BOARD_COUNT]; long draw_list[MAX_DRAW]; board_read(board_list, input); size_t draw_count = draw_read(draw_list, input); // apply draw to each board until one is winning for(size_t i = 0; i < draw_count; i++) { for(size_t j = 0; j < BOARD_COUNT; j++) { if(board_mark(&(board_list[j]), draw_list[i])) { // winning board found, print score long score = board_unmarked_sum(&(board_list[j])); printf("%ld\n", draw_list[i] * score); return; } } } err(1, "no winning board"); } void part2(struct input_str* input) { t_board board_list[BOARD_COUNT]; long draw_list[MAX_DRAW]; board_read(board_list, input); size_t draw_count = draw_read(draw_list, input); // apply draw to each board until one is winning long last_score; for(size_t i = 0; i < draw_count; i++) { for(size_t j = 0; j < BOARD_COUNT; j++) { // skip already winning boards if(board_is_winning(&(board_list[j]))) continue; if(board_mark(&(board_list[j]), draw_list[i])) { // winning board found last_score = draw_list[i] * board_unmarked_sum(&(board_list[j])); } } } // print last winning printf("%ld\n", last_score); } int main() { // read input struct input_str input; input_str_read(&input, INPUT); // do stuff part1(&input); part2(&input); // cleanup & exit input_str_free(&input); return 0; }