solve Day03 in rust

Day03/rust/src/main.rs

@@ -0,0 +1,94 @@
+use std::fs::File;
+use std::io::{self, BufRead, BufReader};
+use std::path::Path;
+
+fn parse_schematic(file_path: &Path) -> io::Result<Vec<String>> {
+    let file = File::open(file_path)?;
+    let reader = BufReader::new(file);
+    reader.lines().collect()
+}
+
+fn get_adjacent_positions(rows: usize, cols: usize, row: usize, col: usize) -> Vec<(usize, usize)> {
+    let mut positions = Vec::new();
+    for i in row.saturating_sub(1)..=(row + 1).min(rows - 1) {
+        for j in col.saturating_sub(1)..=(col + 1).min(cols - 1) {
+            if i != row || j != col {
+                positions.push((i, j));
+            }
+        }
+    }
+    positions
+}
+
+fn find_start_of_number(schematic: &[String], row: usize, mut col: usize) -> usize {
+    while col > 0 && schematic[row].chars().nth(col - 1).unwrap().is_digit(10) {
+        col -= 1;
+    }
+    col
+}
+
+fn extract_full_number(schematic: &mut [String], start_row: usize, start_col: usize) -> i32 {
+    let start_col = find_start_of_number(schematic, start_row, start_col);
+    let mut number = String::new();
+    let mut col = start_col;
+
+    while col < schematic[start_row].len() && schematic[start_row].chars().nth(col).unwrap().is_digit(10) {
+        number.push(schematic[start_row].chars().nth(col).unwrap());
+        schematic[start_row].replace_range(col..=col, ".");
+        col += 1;
+    }
+
+    number.parse::<i32>().unwrap_or(0)
+}
+
+fn find_gears_and_calculate_ratios(schematic: &mut Vec<String>) -> i32 {
+    let rows = schematic.len();
+    let cols = schematic[0].len();
+    let mut total_ratio_sum = 0;
+
+    for row in 0..rows {
+        for col in 0..cols {
+            if schematic[row].chars().nth(col).unwrap() == '*' {
+                let mut part_numbers = Vec::new();
+                for (i, j) in get_adjacent_positions(rows, cols, row, col) {
+                    if schematic[i].chars().nth(j).unwrap().is_digit(10) {
+                        let part_number = extract_full_number(schematic, i, j);
+                        if !part_numbers.contains(&part_number) {
+                            part_numbers.push(part_number);
+                        }
+                    }
+                }
+
+                if part_numbers.len() == 2 {
+                    let gear_ratio = part_numbers[0] * part_numbers[1];
+                    total_ratio_sum += gear_ratio;
+                    println!("Found gear at line {} with ratio {}", row + 1, gear_ratio);
+                }
+            }
+        }
+    }
+
+    total_ratio_sum
+}
+
+fn main() {
+    let test_path = Path::new("../test.txt");
+    let input_path = Path::new("../input.txt");
+
+    match parse_schematic(test_path) {
+        Ok(mut test_schematic) => {
+            let test_result = find_gears_and_calculate_ratios(&mut test_schematic);
+            println!("Test Result: {}", test_result);
+            assert_eq!(test_result, 467835, "Test failed: Expected 467835");
+        }
+        Err(e) => println!("Error reading test file: {}", e),
+    }
+
+    match parse_schematic(input_path) {
+        Ok(mut input_schematic) => {
+            let total_ratio_sum = find_gears_and_calculate_ratios(&mut input_schematic);
+            println!("Total sum of gear ratios: {}", total_ratio_sum);
+        }
+        Err(e) => println!("Error reading input file: {}", e),
+    }
+}