2015 day 6

2015/src/bin/day6.rs

@@ -0,0 +1,53 @@
+use std::cmp;
+
+use aoc::input;
+
+fn main() {
+    let lines = input::read_lines();
+    let mut grid = vec![false; 1_000_000];
+
+    // Part 1
+    for line in &lines {
+        let mut parts = line.split_whitespace();
+        let state = if parts.next() == Some("turn") {
+            parts.next().and_then(|s| Some(s == "on"))
+        } else { // toggle
+            None
+        };
+        let s: Vec<usize> = parts.next().unwrap().split(",")
+            .map(|p| p.parse::<usize>().unwrap()).collect();
+        let e: Vec<usize> = parts.nth(1).unwrap().split(",")
+            .map(|p| p.parse::<usize>().unwrap()).collect();
+        for i in s[0]..=e[0] {
+            for j in s[1]..=e[1] {
+                grid[i * 1000 + j] = match state {
+                    Some(c) => c,
+                    None => !grid[i * 1000 + j]
+                }
+            }
+        }
+    }
+    println!("Lights on: {}", grid.iter().map(|s| if *s { 1 } else { 0 }).sum::<u32>());
+
+    // Part 2
+    let mut grid = vec![0; 1_000_000];
+    for line in &lines {
+        let mut parts = line.split_whitespace();
+        let change: i32 = if parts.next() == Some("turn") {
+            if parts.next().unwrap() == "on" { 1 } else { -1 }
+        } else { // toggle
+            2
+        };
+        let s: Vec<usize> = parts.next().unwrap().split(",")
+            .map(|p| p.parse::<usize>().unwrap()).collect();
+        let e: Vec<usize> = parts.nth(1).unwrap().split(",")
+            .map(|p| p.parse::<usize>().unwrap()).collect();
+        for i in s[0]..=e[0] {
+            for j in s[1]..=e[1] {
+                let current = grid[i * 1000 + j];
+                grid[i * 1000 + j] = cmp::max(current + change, 0);
+            }
+        }
+    }
+    println!("Brightness: {}", grid.iter().sum::<i32>());
+}