day_10: basics done but counting all the possible trails

assets/day_10_trail_map_input

@@ -0,0 +1,8 @@
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732

src/advent_of_code/mod.rs

@@ -78,6 +78,6 @@ pub fn historian_hysteria() {
     // println!("The disk checksum is {}", disk_checksum);
 
     // Tuesday 10
-    let trailhead_score = tue_10::hoof_it(".");
+    let trailhead_score = tue_10::hoof_it("./assets/day_10_trail_map_input");
     println!("The trail head sum score is {}", trailhead_score);
 }

src/advent_of_code/tue_10.rs

@@ -1,5 +1,89 @@
+use utils::read_trail_map_input;
+
 use super::*;
 
 pub fn hoof_it(input: &str) -> usize {
-    0
+    let trail_map = read_trail_map_input(input);
+
+    let vector_of_scores = explore_map(trail_map);
+
+    let mut sum_of_scores: usize = 0;
+
+    println!("The score list is: {:?}", vector_of_scores);
+    // TODO: improve, this is dirty
+    for score in vector_of_scores {
+        sum_of_scores += score;
+    }
+
+    sum_of_scores
+}
+
+pub fn explore_map(map: TrailMap) -> Vec<TrailScore> {
+    let mut trail_score_list: Vec<TrailScore> = vec![];
+
+    for y_index in 0..map.len() {
+        for x_index in 0..map[y_index].len() {
+            if map[y_index][x_index] == 0 {
+                trail_score_list.push(explore_position(x_index, y_index, &map));
+            }
+        }
+    }
+
+    trail_score_list
+}
+
+pub fn explore_position(x: TrailPosition, y: TrailPosition, map: &TrailMap) -> usize {
+    if map[y][x] == 9 {
+        return 1;
+    }
+
+    let mut score_sum: usize = 0;
+    for next_position in get_pos_surroundings(x, y, map) {
+        if map[next_position.1][next_position.0] == map[y][x] + 1 {
+            score_sum += explore_position(next_position.0, next_position.1, map);
+        }
+    }
+
+    score_sum
+}
+
+pub fn get_pos_surroundings(
+    x: TrailPosition,
+    y: TrailPosition,
+    map: &TrailMap,
+) -> Vec<(usize, usize)> {
+    let mut trail_pos_vec: Vec<(usize, usize)> = vec![];
+
+    if x > 0 {
+        trail_pos_vec.push((x - 1, y));
+
+        if y > 0 {
+            trail_pos_vec.push((x - 1, y - 1));
+        }
+        if y < map.len() - 1 {
+            trail_pos_vec.push((x - 1, y + 1));
+        }
+    }
+
+    if x < map[0].len() - 1 {
+        trail_pos_vec.push((x + 1, y));
+
+        if y > 0 {
+            trail_pos_vec.push((x + 1, y - 1));
+        }
+
+        if y < map.len() - 1 {
+            trail_pos_vec.push((x + 1, y + 1));
+        }
+    }
+
+    if y > 0 {
+        trail_pos_vec.push((x, y - 1));
+    }
+
+    if y < map.len() - 1 {
+        trail_pos_vec.push((x, y + 1));
+    }
+
+    trail_pos_vec
 }

src/advent_of_code/types.rs

@@ -79,3 +79,5 @@ pub type DiskChecksum = usize;
 
 // Hoof it
 pub type TrailScore = usize;
+pub type TrailPosition = usize;
+pub type TrailMap = Vec<Vec<TrailPosition>>;

src/advent_of_code/utils.rs

@@ -189,6 +189,23 @@ pub fn read_disk_map_input(input: &str) -> DiskMap {
     disk_map
 }
 
+pub fn read_trail_map_input(input: &str) -> TrailMap {
+    let mut trail_map: TrailMap = vec![];
+
+    for line in read_to_string(input).unwrap().lines() {
+        let mut trail_row: Vec<usize> = vec![];
+        for position in line.chars() {
+            if let Some(digit) = position.to_digit(10) {
+                trail_row.push(digit as usize);
+            }
+        }
+
+        trail_map.push(trail_row);
+    }
+
+    trail_map
+}
+
 pub fn calc_distance<T>(num_1: T, num_2: T) -> T
 where
     T: PartialOrd + Sub<Output = T>,