Day 3 (2016) solution.

2016/twenty16/src/day1.rs

@@ -62,10 +62,8 @@ pub fn run_day_1() -> Solution {
             'W' => current_position.x = current_position.x - amount,
             _ => current_position.x = current_position.x,
         };
-       // log the cooordinates, check to see if has been visited.
     }
 
-    // println!("{:?}", visited_coords);
     /*
      * SOLUTION
      */

2016/twenty16/src/day3.rs

@@ -0,0 +1,88 @@
+use crate::Solution;
+use std::fs;
+
+pub fn day_3() -> Solution {
+    let triangles_file = fs::read_to_string("./sources/day3.txt").expect("unable to read file");
+    let triangles = triangles_file.split("\n");
+    let mut valid_triangles: i32 = 0;
+    let mut column_1: Vec<i32> = vec![];
+    let mut column_2: Vec<i32> = vec![];
+    let mut column_3: Vec<i32> = vec![];
+    
+    // Part 1.
+    for triangle in triangles {
+        // Skip if empty line.
+        if triangle.len() < 1 {
+            continue;
+        }
+        let isolate_sides = triangle.split("  ");
+        let mut valid_sides: Vec<i32> = Vec::new();
+        for side in isolate_sides {
+            // Skip if found empty side value.
+            if side.len() < 1 {
+                continue;
+            } else {
+                let side_value: i32 = side.trim().parse().unwrap();
+                valid_sides.push(side_value); 
+            }
+        }
+        let is_valid_triangle = check_if_valid_triangle(valid_sides.clone());
+        if is_valid_triangle {
+            valid_triangles += 1;
+        }
+        column_1.push(valid_sides[0]);
+        column_2.push(valid_sides[1]);
+        column_3.push(valid_sides[2]);
+    }
+    let p1_solution = valid_triangles.to_string();
+    // Part 2.
+    valid_triangles = 0;
+    // slice each column into groups of 3.
+    for vert_triangle in column_1.chunks(3) {
+        let is_valid_triangle = check_if_valid_triangle(vert_triangle.to_vec());
+        if is_valid_triangle {
+            valid_triangles += 1;
+        }
+    }
+    for vert_triangle in column_2.chunks(3) {
+       let is_valid_triangle = check_if_valid_triangle(vert_triangle.to_vec());
+        if is_valid_triangle {
+            valid_triangles += 1;
+        }
+    }
+    for vert_triangle in column_3.chunks(3) {
+        let is_valid_triangle = check_if_valid_triangle(vert_triangle.to_vec());
+        if is_valid_triangle {
+            valid_triangles += 1;
+        }
+    }
+    let p2_solution = valid_triangles.to_string();
+
+    let mut answers = String::new();
+    let part_1 = "Part 1: ".to_string();
+    let newline = "\n".to_string();
+    answers.push_str(&part_1);
+    answers.push_str(&p1_solution);
+    answers.push_str(&newline);
+    let part_2 = "Part 2: ".to_string();
+    answers.push_str(&part_2);
+    answers.push_str(&p2_solution);
+
+    let solution = Solution {
+        day: 3,
+        answer: answers,
+    };
+    solution
+}
+
+fn check_if_valid_triangle(sides: Vec<i32>) -> bool {
+    let side_a = sides[0];
+    let side_b = sides[1];
+    let side_c = sides[2];
+    if side_a + side_b <= side_c || side_a + side_c <= side_b || side_b + side_c <= side_a {
+        false
+    } else {
+        true
+    }
+    
+}

2016/twenty16/src/main.rs

@@ -1,6 +1,7 @@
 use tabled::{Table, Tabled};
 pub mod day1;
 pub mod day2;
+pub mod day3;
 
 #[derive(Tabled)]
 pub struct Solution {
@@ -12,8 +13,10 @@ fn main() {
     let mut rows = Vec::new();
     let day1 = day1::run_day_1();
     let day2 = day2::run_day_2();
+    let day3 = day3::day_3();
     rows.push(day1);
     rows.push(day2);
+    rows.push(day3);
 
     let table = Table::new(rows);