problem 3

src/main.rs

@@ -1,11 +1,13 @@
 extern crate reqwest;
 extern crate tempfile;
 
-use crate::problem1::part1::Problem1;
+use crate::problem1::lib::Problem1;
-use crate::problem2::part2::Problem2;
+use crate::problem2::lib::Problem2;
+use crate::problem3::lib::Problem3;
 
 mod problem1;
 mod problem2;
+mod problem3;
 mod util;
 
 
@@ -23,7 +25,12 @@ fn main() {
     // problem1.run_part1();
     // problem1.run_part2();
 
-    let problem2 = Problem2::new(&util::get_problem(2));
+    //let problem2 = Problem2::new(&util::get_problem(2));
-    problem2.run_part1();
+    //problem2.run_part1();
-    problem2.run_part2();
+    //problem2.run_part2();
-}
+
+    let problem3 = Problem3::new(&util::get_problem(3));
+    problem3.run_part1();
+    problem3.run_part2();
+
+}

src/problem1/mod.rs

@@ -1 +1 @@
-pub mod part1;
+pub mod lib;

src/problem2/mod.rs

@@ -1 +1 @@
-pub mod part2;
+pub mod lib;

src/problem3/lib.rs

@@ -0,0 +1,75 @@
+/*
+Starting at the top-left corner of your map and following a slope of right 3 and down 1, how many trees would you encounter?
+*/
+
+use crate::Problem;
+
+pub struct Problem3 {
+    map: Vec<Vec<i32>>,
+}
+
+impl Problem3 {
+    fn get_tile(&self, x: i32, y: i32) -> i32 {
+        let dim_y = self.map.len() as i32;
+        let dim_x = self.map.get(0).unwrap().len() as i32;
+
+        let ind_x = (x % dim_x) as usize;
+        let ind_y = (y % dim_y) as usize;
+
+        *self.map.get(ind_y).unwrap().get(ind_x).unwrap()
+    }
+
+    fn traverse(&self, dx: i32, dy: i32) -> i64 {
+        let mut x = 0;
+        
+        let mut count = 0;
+
+        for y in ((dy as usize)..self.map.len()).step_by(dy as usize) {
+            x += dx;
+            if self.get_tile(x as i32, y as i32) == 1 {
+                count += 1;
+//                println!("tree at {}, {}", x, y);
+            }
+        }
+        count as i64 
+    }
+}
+
+impl Problem for Problem3 {
+    fn new(input: &String) -> Self {
+        Problem3 {
+            map: input
+                .split("\n")
+                .filter_map(|s| {
+                    let s = s.trim();
+                    if !s.is_empty() {
+                        let mut accum = Vec::new();
+                        for i in s.chars() {
+                            if i == '#' {
+                                accum.push(1);
+                            } else {
+                                accum.push(0);
+                            }
+                        }
+                        Some(accum)
+                    } else {
+                        None
+                    }
+                }).collect(),
+        }
+    }
+
+    fn run_part1(&self) {
+       
+        let v : i64 = self.traverse(1, 1) *
+            self.traverse(3, 1) *
+            self.traverse(5, 1) *
+            self.traverse(7, 1) *
+            self.traverse(1, 2);
+        println!("{}", v);
+    }
+
+    fn run_part2(&self) {
+    }
+}
+

src/problem3/mod.rs

@@ -0,0 +1 @@
+pub mod lib;