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-rw-r--r--2018/src/bin/day_11.rs66
1 files changed, 66 insertions, 0 deletions
diff --git a/2018/src/bin/day_11.rs b/2018/src/bin/day_11.rs
new file mode 100644
index 0000000..0e458a3
--- /dev/null
+++ b/2018/src/bin/day_11.rs
@@ -0,0 +1,66 @@
+extern crate advent_of_code_2018;
+use advent_of_code_2018::*;
+
+use std::error::Error;
+use std::i32;
+
+// cargo watch -cs "cargo run --release --bin day_11"
+
+fn main() -> Result<(), Box<Error>> {
+ let input = 1723;
+
+ println!("Input: {:?}", input);
+
+ let powers = precompute_powers(input);
+
+ let power_per_size = (1..300).map(|size| {
+ (1..302-size).map(|left| {
+ (1..302-size).map(|top| {
+ (power_for_block(left, top, size, &powers), (left, top, size))
+ }).max_by_key(|(p, _)| *p).unwrap()
+ }).max_by_key(|(p, _)| *p).unwrap()
+ }).collect::<Vec<_>>();
+
+ let (max_power_at_size_3, coordinate_at_size_3) = power_per_size[2]; // index from 0 vs 1
+ debug!(max_power_at_size_3);
+ debug!(coordinate_at_size_3);
+
+ let (max_power, coordinate) = power_per_size.iter().max_by_key(|(p, _)| p).unwrap();
+
+ debug!(max_power);
+ debug!(coordinate);
+
+ Ok(())
+}
+
+fn power_for_block(left: i32, top: i32, size: i32, powers: &[[i32;300];300]) -> i32 {
+ (left..left+size).map(|x| {
+ (top..top+size).map(|y| {
+ powers[x as usize - 1][y as usize - 1]
+ }).sum::<i32>()
+ }).sum()
+}
+
+fn precompute_powers(input: i32) -> [[i32;300];300] {
+ let mut powers: [[i32;300];300] = [[0;300];300];
+ for x in 1..301 {
+ for y in 1..301 {
+ powers[x as usize - 1][y as usize - 1] = power_from_coordinates(x, y, input);
+ }
+ }
+ powers
+}
+
+fn power_from_coordinates(x: i32, y: i32, input: i32) -> i32 {
+ let rack_id = x + 10;
+ ((((rack_id * y) + input) * rack_id / 100) % 10) - 5
+}
+
+
+#[test]
+fn power_from_coord_example() {
+ assert_eq!(power_from_coordinates(3, 5, 8), 4);
+ assert_eq!(power_from_coordinates(122, 79, 57), -5);
+ assert_eq!(power_from_coordinates(217,196, 39), 0);
+ assert_eq!(power_from_coordinates(101, 153, 71), 4);
+}