From 5d230e12f65b816881d084b8fbe2c52070105ceb Mon Sep 17 00:00:00 2001
From: Justin Worthe <justin@worthe-it.co.za>
Date: Sun, 3 Dec 2017 10:27:14 +0200
Subject: Day 3: Spirals...

---
 src/bin/day_3.rs | 62 ++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs       | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 144 insertions(+)
 create mode 100644 src/bin/day_3.rs

(limited to 'src')

diff --git a/src/bin/day_3.rs b/src/bin/day_3.rs
new file mode 100644
index 0000000..69ded88
--- /dev/null
+++ b/src/bin/day_3.rs
@@ -0,0 +1,62 @@
+extern crate advent_of_code_2017;
+use advent_of_code_2017::*;
+
+use std::collections::HashMap;
+
+fn main() {
+    use Direction::*;
+    
+    let args = AdventArgs::init();
+    let input = args.one_number_input().unwrap();
+
+    let mut memory: HashMap<Point, i32> = HashMap::new();
+    let mut last_allocated = 1;
+    
+    let mut current = Point {
+        x: 0,
+        y: 0
+    };
+    memory.insert(current, last_allocated);
+
+    let mut steps_per_direction = 1;
+    let mut steps_to_next_turn = 1;
+    let mut turns_to_spiral_increase = 2;
+
+    let mut current_index = 1;
+    let mut current_direction = Right;
+
+    while (args.part == 1 && current_index != input) || (args.part == 2 && last_allocated < input) {
+        current = current.shift(&current_direction);
+        current_index += 1;
+
+        steps_to_next_turn -= 1;
+        if steps_to_next_turn == 0 {
+            current_direction = current_direction.rotate_left();
+            turns_to_spiral_increase -= 1;
+            if turns_to_spiral_increase == 0 {
+                steps_per_direction += 1;
+                turns_to_spiral_increase = 2;
+            }
+            
+            steps_to_next_turn = steps_per_direction;
+        }
+
+        if args.part == 2 {
+            last_allocated = memory.get(&current.left()).cloned().unwrap_or(0) +
+                memory.get(&current.right()).cloned().unwrap_or(0) +
+                memory.get(&current.up()).cloned().unwrap_or(0) +
+                memory.get(&current.down()).cloned().unwrap_or(0) +
+                memory.get(&current.up().left()).cloned().unwrap_or(0) +
+                memory.get(&current.up().right()).cloned().unwrap_or(0) +
+                memory.get(&current.down().left()).cloned().unwrap_or(0) +
+                memory.get(&current.down().right()).cloned().unwrap_or(0);
+            
+            memory.insert(current, last_allocated);
+        }
+    }
+
+    println!("{:?}", current);
+    println!("Distance: {}", current.x.abs() + current.y.abs());
+    println!("Last Allocated Value: {}", last_allocated);
+    
+}
diff --git a/src/lib.rs b/src/lib.rs
index 5d3721f..caa8881 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -58,6 +58,10 @@ impl AdventArgs {
             .map(|line| line.trim().to_string())
             .collect()
     }
+
+    pub fn one_number_input(&self) -> Result<i32, std::num::ParseIntError> {
+        self.input[0].parse()
+    }
 }
 
 pub fn parse_space_separated_ints(line: &String) -> Result<Vec<i32>, std::num::ParseIntError> {
@@ -65,3 +69,81 @@ pub fn parse_space_separated_ints(line: &String) -> Result<Vec<i32>, std::num::P
         .map(|x| x.parse::<i32>())
         .collect()
 }
+
+
+#[derive(Hash, Eq, PartialEq, Debug, Clone, Copy)]
+pub struct Point {
+    pub x: i32,
+    pub y: i32
+}
+
+impl Point {
+    pub fn up(&self) -> Point {
+        Point {
+            y: self.y-1,
+            ..*self
+        }
+    }
+
+    pub fn down(&self) -> Point {
+        Point {
+            y: self.y+1,
+            ..*self
+        }
+    }
+
+    pub fn left(&self) -> Point {
+        Point {
+            x: self.x-1,
+            ..*self
+        }
+    }
+
+    pub fn right(&self) -> Point {
+        Point {
+            x: self.x+1,
+            ..*self
+        }
+    }
+
+    pub fn shift(&self, dir: &Direction) -> Point {
+        use Direction::*;
+        
+        match *dir {
+            Right => self.right(),
+            Left => self.left(),
+            Up => self.up(),
+            Down => self.down()
+        }
+    }
+}
+
+#[derive(Debug)]
+pub enum Direction {
+    Left,
+    Up,
+    Down,
+    Right
+}
+
+impl Direction {
+    pub fn rotate_left(&self) -> Direction {
+        use Direction::*;
+        match *self {
+            Right => Up,
+            Up => Left,
+            Left => Down,
+            Down => Right
+        }
+    }
+
+    pub fn rotate_right(&self) -> Direction {
+        use Direction::*;
+        match *self {
+            Right => Down,
+            Up => Right,
+            Left => Up,
+            Down => Left
+        }
+    }
+}
-- 
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