Files
adventofcode2023/day3/src/main.rs
Acvaxoort f3b2bd95e4 day 3
2023-12-03 11:23:06 +01:00

104 lines
3.8 KiB
Rust

use std::fs::read_to_string;
fn main() {
// store of numbers
let mut numbers: Vec<i32> = Vec::new();
// whether the number counts
let mut numbers_occur: Vec<bool> = Vec::new();
// spatial information about the data
// natural number is index in numbers table, negative are special
let mut adjacency_table: Vec<i32> = Vec::new();
const EMPTY_SPACE: i32 = -1;
const SYMBOL: i32 = -2;
const GEAR: i32 = -3;
let mut row_counter = 0;
let mut col_counter = 0;
for line in read_to_string("input.txt").unwrap().lines() {
let mut parsing_number = false;
let mut constructed_number = 0;
if line.is_empty() {
break;
}
col_counter += 1;
row_counter = line.len() as i32;
for c in line.chars() {
match c {
'0'..='9' => {
let value = c as i32 - '0' as i32;
constructed_number = constructed_number * 10 + value;
parsing_number = true;
adjacency_table.push(numbers.len() as i32);
}
_ => {
if parsing_number {
numbers.push(constructed_number);
numbers_occur.push(false);
parsing_number = false;
constructed_number = 0;
}
match c {
'.' => {
adjacency_table.push(EMPTY_SPACE);
}
'*' => {
adjacency_table.push(GEAR);
}
_ => {
adjacency_table.push(SYMBOL);
}
}
}
}
}
if parsing_number {
numbers.push(constructed_number);
numbers_occur.push(false);
}
}
let mut sum1 = 0;
let mut sum2 = 0;
for row in 0 .. row_counter {
for col in 0 ..col_counter {
let value = adjacency_table[(row * col_counter + col) as usize];
if value == SYMBOL || value == GEAR {
let mut num1 = -1;
let mut num2 = -1;
let mut valid_gear = value == GEAR;
for offset_row in -1..2 {
for offset_col in -1..2 {
let new_row = row + offset_row;
let new_col = col + offset_col;
if new_row >= 0 && new_row < row_counter && new_col >= 0 && new_col < col_counter {
let new_value = adjacency_table[(new_row * col_counter + new_col) as usize];
if new_value >= 0 {
numbers_occur[new_value as usize] = true;
if value == GEAR {
if num1 == -1 {
num1 = new_value;
} else if num1 != new_value {
if num2 == -1 {
num2 = new_value;
} else if num2 != new_value {
valid_gear = false;
}
}
}
}
}
}
}
if valid_gear && num1 >= 0 && num2 >= 0 {
sum2 += numbers[num1 as usize] * numbers[num2 as usize];
}
}
}
}
for i in 0 .. numbers.len() {
if numbers_occur[i] {
sum1 += numbers[i];
}
}
println!("Sum1: {}", sum1);
println!("Sum2: {}", sum2);
}