day19

2 files changed, 72 insertions, 3 deletions

diff --git a/input19 b/input19
new file mode 100644
index 0000000..cc2d321
--- /dev/null
+++ b/input19
@@ -0,0 +1 @@
+109,424,203,1,21101,11,0,0,1105,1,282,21101,0,18,0,1106,0,259,1202,1,1,221,203,1,21101,0,31,0,1105,1,282,21102,1,38,0,1106,0,259,20101,0,23,2,22102,1,1,3,21101,1,0,1,21101,0,57,0,1106,0,303,1202,1,1,222,21002,221,1,3,21001,221,0,2,21102,1,259,1,21101,80,0,0,1105,1,225,21102,1,117,2,21102,1,91,0,1105,1,303,1202,1,1,223,20102,1,222,4,21101,0,259,3,21101,0,225,2,21101,225,0,1,21101,118,0,0,1105,1,225,21001,222,0,3,21101,20,0,2,21102,1,133,0,1105,1,303,21202,1,-1,1,22001,223,1,1,21101,0,148,0,1106,0,259,2101,0,1,223,20102,1,221,4,21001,222,0,3,21101,0,16,2,1001,132,-2,224,1002,224,2,224,1001,224,3,224,1002,132,-1,132,1,224,132,224,21001,224,1,1,21102,195,1,0,105,1,108,20207,1,223,2,21002,23,1,1,21102,-1,1,3,21101,0,214,0,1105,1,303,22101,1,1,1,204,1,99,0,0,0,0,109,5,1201,-4,0,249,22102,1,-3,1,22101,0,-2,2,21202,-1,1,3,21102,1,250,0,1106,0,225,22102,1,1,-4,109,-5,2105,1,0,109,3,22107,0,-2,-1,21202,-1,2,-1,21201,-1,-1,-1,22202,-1,-2,-2,109,-3,2106,0,0,109,3,21207,-2,0,-1,1206,-1,294,104,0,99,21202,-2,1,-2,109,-3,2105,1,0,109,5,22207,-3,-4,-1,1206,-1,346,22201,-4,-3,-4,21202,-3,-1,-1,22201,-4,-1,2,21202,2,-1,-1,22201,-4,-1,1,21201,-2,0,3,21101,343,0,0,1105,1,303,1105,1,415,22207,-2,-3,-1,1206,-1,387,22201,-3,-2,-3,21202,-2,-1,-1,22201,-3,-1,3,21202,3,-1,-1,22201,-3,-1,2,21201,-4,0,1,21101,0,384,0,1105,1,303,1105,1,415,21202,-4,-1,-4,22201,-4,-3,-4,22202,-3,-2,-2,22202,-2,-4,-4,22202,-3,-2,-3,21202,-4,-1,-2,22201,-3,-2,1,22101,0,1,-4,109,-5,2105,1,0
diff --git a/src/main.rs b/src/main.rs
index 439f456..93dbfaa 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,8 +4,7 @@ use std::fs::{self, File};
 use std::io::prelude::*;
 use std::cmp;
 use std::cmp::Ordering;
-use std::collections::VecDeque;
-use std::collections::HashMap;
+use std::collections::{VecDeque, HashMap, HashSet};
 
 #[derive(Eq, PartialEq, Clone, Copy, Debug, Hash)]
 struct Point {
@@ -1826,8 +1825,77 @@ fn day17() {
     println!("17b: {}", output);
 }
 
+fn check_position(program: &[isize], x: isize, y: isize) -> isize {
+    let mut computer = IntComputer::new(program);
+    computer.suspend_on_output = true;
+    let mut output = 0;
+    computer.input.push_back(x);
+    computer.input.push_back(y);
+    loop {
+        match computer.run_program() {
+            ProgramState::SUSPENDED => output = computer.output.pop_front().unwrap(),
+            ProgramState::HALTED => break,
+            _ => {}
+        }
+    }
+    output
+}
+
+fn check_square_fits(map: &HashSet<(isize, isize)>, size: isize, x: isize, y: isize) -> bool {
+    for i in 0..size {
+        for j in 0..size {
+            if !map.contains(&(x-j, y-i)) {
+                return false;
+            }
+        }
+    }
+    true
+}
+
+fn day19() {
+    let input = read_file("input19");
+    let input = input.trim_end();
+    let program : Vec<isize> = input.split(',')
+                                    .map(|x| x.parse::<isize>().unwrap())
+                                    .collect();
+
+    let mut sum = 0;
+    for x in 0..50 {
+        for y in 0..50 {
+            sum += check_position(&program, x, y);
+        }
+    }
+    println!("19a: {}", sum);
+
+    let mut map = HashSet::new();
+    let mut tractor_begin = 0;
+    'outer: for y in 0..1500 {
+        let mut was_tractor = false;
+        for x in tractor_begin..1500 {
+            let state = check_position(&program, x, y);
+            if state == 0 {
+                if was_tractor {
+                    /* any further position on the x axis will be space */
+                    break;
+                }
+            } else {
+                if !was_tractor {
+                    was_tractor = true;
+                    tractor_begin = x;
+                }
+                map.insert((x, y));
+                if check_square_fits(&map, 100, x, y) {
+                    println!("19b: {}", (x-99)*10_000 + (y-99));
+                    break 'outer;
+                }
+            }
+            sum += state;
+        }
+    }
+}
+
 fn main() {
-    day17();
+    day19();
 }
 
 #[cfg(test)]