From 9918141a472170a8562ca2d5d6d1c3b06a2e8a00 Mon Sep 17 00:00:00 2001
From: Justin Worthe <justin@worthe-it.co.za>
Date: Thu, 6 Dec 2018 07:32:35 +0200
Subject: Day 6: Manhattan distances and coordinates

---
 inputs/6.txt     | 50 ++++++++++++++++++++++++++++++++
 src/bin/day_6.rs | 87 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 136 insertions(+), 1 deletion(-)
 create mode 100644 inputs/6.txt

diff --git a/inputs/6.txt b/inputs/6.txt
new file mode 100644
index 0000000..e544bbd
--- /dev/null
+++ b/inputs/6.txt
@@ -0,0 +1,50 @@
+195, 221
+132, 132
+333, 192
+75, 354
+162, 227
+150, 108
+46, 40
+209, 92
+153, 341
+83, 128
+256, 295
+311, 114
+310, 237
+99, 240
+180, 337
+332, 176
+212, 183
+84, 61
+275, 341
+155, 89
+169, 208
+105, 78
+151, 318
+92, 74
+146, 303
+184, 224
+285, 348
+138, 163
+216, 61
+277, 270
+130, 155
+297, 102
+197, 217
+72, 276
+299, 89
+357, 234
+136, 342
+346, 221
+110, 188
+82, 183
+271, 210
+46, 198
+240, 286
+128, 95
+111, 309
+108, 54
+258, 305
+241, 157
+117, 162
+96, 301
diff --git a/src/bin/day_6.rs b/src/bin/day_6.rs
index 008ea56..16c8782 100644
--- a/src/bin/day_6.rs
+++ b/src/bin/day_6.rs
@@ -4,15 +4,100 @@ use advent_of_code_2018::*;
 use std::error::Error;
 use std::path::PathBuf;
 
+use std::collections::{HashSet, HashMap};
+
 // cargo watch -cs "cargo run --release --bin day_6"
 
 fn main() -> Result<(), Box<Error>> {
     let input = read_file(&PathBuf::from("inputs/6.txt"))?;
+    let coordinates = input.iter().map(|line| {
+        let mut split = line.split(|c: char| !c.is_numeric());
+        let x: i32 = split.next().unwrap().parse().unwrap();
+        let _ = split.next();
+        let y: i32 = split.next().unwrap().parse().unwrap();
+        (x, y)
+    }).collect::<Vec<_>>();
+    debug!(coordinates);
+
+    let min_x = coordinates.iter().map(|(x, _)| x).min().unwrap().clone();
+    let max_x = coordinates.iter().map(|(x, _)| x).max().unwrap().clone();
+    let min_y = coordinates.iter().map(|(_, y)| y).min().unwrap().clone();
+    let max_y = coordinates.iter().map(|(_, y)| y).max().unwrap().clone();
+    
+    debug!(min_x);
+    debug!(max_x);
+    debug!(min_y);
+    debug!(max_y);
+
+    let mut infinite = HashSet::new();
+    for x in min_x..max_x+1 {
+        for y in &[0, max_y] {
+            if let Some(coord) = find_closest(&coordinates, x, *y) {
+                infinite.insert(coord);
+            }
+        }
+    }
+    for y in min_y..max_y+1 {
+        for x in &[0, max_x] {
+            if let Some(coord) = find_closest(&coordinates, *x, y) {
+                infinite.insert(coord);
+            }
+        }
+    }
 
-    println!("Input: {:?}", input);
+    debug!(infinite);
+    
 
+    let mut areas = HashMap::new();
+    for x in min_x..max_x+1 {
+        for y in min_y..max_y+1 {
+            if let Some(coord) = find_closest(&coordinates, x, y) {
+                *areas.entry(coord).or_insert(0) += 1;
+            }
+        }
+    }
 
+    debug!(areas);
 
+    let biggest_non_infinite = areas.iter()
+        .filter(|(k,_)| !infinite.contains(&k))
+        .max_by_key(|(_,v)| *v);
+    debug!(biggest_non_infinite);
+    
 
+
+    let safe_distance = 10000;
+    let mut safe_size = 0;
+    for x in min_x..max_x+1 {
+        for y in min_y..max_y+1 {
+            let distance_sum: i32 = coordinates.iter()
+                .map(|(x1, y1)| manhattan_distance(*x1, *y1, x, y))
+                .sum();
+            if distance_sum < safe_distance {
+                safe_size += 1;
+            }
+        }
+    }
+    debug!(safe_size);
+    
     Ok(())
 }
+
+fn find_closest(coordinates: &Vec<(i32, i32)>, x: i32, y: i32) -> Option<usize> {
+    let mut distances = coordinates.iter()
+        .map(|(x1, y1)| manhattan_distance(*x1, *y1, x, y))
+        .enumerate()
+        .collect::<Vec<_>>();
+    distances.sort_by_key(|(_, d)| *d);
+
+    if distances[0] == distances[1] {
+        None
+    }
+    else {
+        distances.first().map(|(i, _)| *i)
+    }
+}
+
+fn manhattan_distance(x1: i32, y1: i32, x2: i32, y2: i32) -> i32 {
+    (x2-x1).abs() + (y2-y1).abs()
+}
-- 
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