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#include <stdlib.h>
#include <stdio.h>
#include <err.h>
#include <stdbool.h>
#include "input.h"
#define INPUT "input/05.txt"
#define EXPECTED1 6113
#define EXPECTED2 20373
#define RESOLUTION 1000
#define CMP(a, b) ((a > b) - (a < b))
typedef struct {
long p1[2];
long p2[2];
} t_line;
/* sooooo thats about 80KB of memory on my end */
int space1[RESOLUTION][RESOLUTION];
int space2[RESOLUTION][RESOLUTION];
void line_list_read(t_line* line_list, struct input_str* input) {
for(size_t i = 0; i < input->line_count; i++) {
char* start = input->lines[i];
char* end = start;
line_list[i].p1[0] = strtol(start, &end, 0);
start = end + 1; //skip comma
line_list[i].p1[1] = strtol(start, &end, 0);
start = end + 4; // skip arrow
line_list[i].p2[0] = strtol(start, &end, 0);
start = end + 1; // skip comma
line_list[i].p2[1] = strtol(start, &end, 0);
}
}
void line_print(t_line* line) {
printf("%ld,%ld -> %ld,%ld\n", line->p1[0], line->p1[1], line->p2[0], line->p2[1]);
}
void part1(struct input_str* input) {
t_line* line_list = malloc(input->line_count * sizeof(t_line));
line_list_read(line_list, input);
for(size_t l = 0; l < input->line_count; l++) {
t_line line = line_list[l];
long x1 = line.p1[0];
long y1 = line.p1[1];
long x2 = line.p2[0];
long y2 = line.p2[1];
if(x1 != x2 && y1 != y2) // ignore those for part1
continue;
long dx = -1 * CMP(x1, x2);
long dy = -1 * CMP(y1, y2);
long x, y;
// beware the monster loop
for(x = x1, y = y1; (x != x2 + dx || x1 == x2) && (y != y2 + dy || y1 == y2); x += dx, y += dy) {
space1[x][y]++;
}
}
// count space points with at least a value of 2
int result = 0;
for(int x = 0; x < RESOLUTION; x++) {
for(int y = 0; y < RESOLUTION; y++) {
if(space1[x][y] >= 2)
result++;
}
}
CHECK(result, EXPECTED1);
free(line_list);
}
void part2(struct input_str* input) {
t_line* line_list = malloc(input->line_count * sizeof(t_line));
line_list_read(line_list, input);
for(size_t l = 0; l < input->line_count; l++) {
t_line line = line_list[l];
long x1 = line.p1[0];
long y1 = line.p1[1];
long x2 = line.p2[0];
long y2 = line.p2[1];
long dx = -1 * CMP(x1, x2);
long dy = -1 * CMP(y1, y2);
long x, y;
for(x = x1, y = y1; (x != x2 + dx || x1 == x2) && (y != y2 + dy || y1 == y2); x += dx, y += dy) {
space2[x][y]++;
}
}
// count space points with at least a value of 2
int result = 0;
for(int x = 0; x < RESOLUTION; x++) {
for(int y = 0; y < RESOLUTION; y++) {
if(space2[x][y] >= 2)
result++;
}
}
CHECK(result, EXPECTED2);
free(line_list);
}
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;
}
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