AdventOfCode/C/2015/Day_3/main.c

#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>

#define IMP
#include "../../file.h"
#include "../../str.h"

struct point {
	long x, y;
};

int
main(int argc, char *argv[])
{
	enum file_err ferr;
	long res = 0;

	size_t i = 0;
	size_t j = 0;

	struct point p = {0};

	struct str str_input = {0};

	char *raw_input = NULL;
	size_t raw_input_size = 0;

	raw_input = (char *) file_read_all("./input.txt", 
					   &raw_input_size,
					   &ferr);
	if ( ferr != FILE_ERR_OK ) {
		fprintf(stderr, "Failed to open file: %s\n", 
			file_err_to_cstr(ferr));
		exit(EXIT_FAILURE);
	}

	str_input = str_from_cstr(raw_input, raw_input_size);


	if ( argc == 1 ) {
		struct point *uniqs = NULL;
		size_t uniqs_size = 0;

		struct point *points = NULL;
		size_t points_size = 1;

		points = calloc(str_input.size + 1, sizeof(*points));

		for ( i = 0; i < str_input.size; ++i ) {
			struct point *it = (points + i + 1);
			p = points[i];

			*it = p;
			switch ( str_input.data[i] ) {
			case '>':
				++it->x;
				break;
			case '^':
				--it->y;
				break;
			case '<':
				--it->x;
				break;
			case 'v':
				++it->y;
				break;
			}
			++points_size;
		}

		uniqs = calloc(points_size, sizeof(*uniqs));

		for ( i = 0; i < points_size; ++i ) {
			p = points[i];
			for ( j = 0; j < uniqs_size; ++j ) {
				if ( uniqs[j].x == p.x && uniqs[j].y == p.y ) {
					goto outer_continue_p1;
				}
			}
			uniqs[uniqs_size++] = p;
outer_continue_p1:	;
		}

		res = (long) uniqs_size;

		free(points);
		free(uniqs);
	} else {
		struct point *uniqs = NULL;
		size_t uniqs_size = 0;

		struct point *rs = NULL;
		size_t rs_size = 0;
		struct point *hs = NULL;
		size_t hs_size = 0;

		/* Need only half of str_points.size, but who cares. */
		rs = calloc(str_input.size, sizeof(*rs));
		hs = calloc(str_input.size, sizeof(*hs));

		for ( i = 0; i < str_input.size; ++i ) {
			struct point *it = NULL;
			if ( (i & 1) == 0 ) {
				p = hs[hs_size];
				it = &hs[(hs_size++) + 1];
			} else {
				p = rs[rs_size];
				it = &rs[(rs_size++) + 1];
			}

			*it = p;
			switch ( str_input.data[i] ) {
			case '>':
				++it->x;
				break;
			case '^':
				--it->y;
				break;
			case '<':
				--it->x;
				break;
			case 'v':
				++it->y;
				break;
			}
		}

		uniqs = calloc(rs_size + hs_size, sizeof(*uniqs));

		for ( i = 0; i < str_input.size; ++i ) {
			if ( i < hs_size ) {
				p = hs[i];
				for ( j = 0; j < uniqs_size; ++j ) {
					if ( uniqs[j].x == p.x && uniqs[j].y == p.y ) {
						goto not_uniq_1;
					}
				}
				uniqs[uniqs_size++] = p;
not_uniq_1:			;
			}
			if ( i < rs_size ) {
				p = rs[i];
				for ( j = 0; j < uniqs_size; ++j ) {
					if ( uniqs[j].x == p.x && uniqs[j].y == p.y ) {
						goto not_uniq_2;
					}
				}
				uniqs[uniqs_size++] = p;
not_uniq_2:			;
			}
		}

		res = (long) uniqs_size;

		free(hs);
		free(rs);

		free(uniqs);
	}

	printf("Result: %ld\n", res);

	free(raw_input);

	(void) argc; (void) argv;
	return 0;
}