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#include <stdlib.h>
#include <stdio.h>
#include <limits.h>
#include "input.h"
#define ABS(x) (x < 0 ? -(x) : x)
#define MIN(x, y) (x < y ? x : y)
#define INPUT "input/07.txt"
#define INPUT_DOMAIN_MAX 2000
#define EXPECTED1 349769L
#define EXPECTED2 99540554L
void part1(struct input_str* input) {
char* start = input->lines[0];
char* end = start;
int sub_count_by_alt[INPUT_DOMAIN_MAX] = { 0 };
// parse input
long sub_count = 0;
while(*end != '\n') {
long alt = strtol(start, &end, 0);
start = end;
if(*end == ',')
start++;
sub_count_by_alt[alt]++;
sub_count++;
}
// brute force
long fuel_min = LONG_MAX;
for(int a = 0; a < INPUT_DOMAIN_MAX; a++) {
long current_fuel = 0;
for(int b = 0; b < INPUT_DOMAIN_MAX; b++) {
current_fuel += sub_count_by_alt[b] * ABS(b - a);
}
fuel_min = MIN(fuel_min, current_fuel);
}
CHECK(fuel_min, EXPECTED1);
}
long compute_fuel(int distance) {
long fuel = 0;
for(int i = 1; i <= distance; i++) {
fuel += i;
}
return fuel;
}
void part2(struct input_str* input) {
char* start = input->lines[0];
char* end = start;
int sub_count_by_alt[INPUT_DOMAIN_MAX] = { 0 };
// parse input
long sub_count = 0;
while(*end != '\n') {
long alt = strtol(start, &end, 0);
start = end;
if(*end == ',')
start++;
sub_count_by_alt[alt]++;
sub_count++;
}
// brute force
long fuel_min = LONG_MAX;
for(int a = 0; a < INPUT_DOMAIN_MAX; a++) {
long current_fuel = 0;
for(int b = 0; b < INPUT_DOMAIN_MAX; b++) {
current_fuel += sub_count_by_alt[b] * compute_fuel(ABS(b - a));
}
fuel_min = MIN(fuel_min, current_fuel);
}
CHECK(fuel_min, EXPECTED2);
}
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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