Progress to day 11

9-encoding_error/Cargo.lock

@@ -0,0 +1,23 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "either"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e78d4f1cc4ae33bbfc157ed5d5a5ef3bc29227303d595861deb238fcec4e9457"
+
+[[package]]
+name = "encoding_error"
+version = "0.1.0"
+dependencies = [
+ "itertools",
+]
+
+[[package]]
+name = "itertools"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "37d572918e350e82412fe766d24b15e6682fb2ed2bbe018280caa810397cb319"
+dependencies = [
+ "either",
+]

9-encoding_error/Cargo.toml

@@ -7,3 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+itertools = "0.10.0"

9-encoding_error/src/main.rs

@@ -1,3 +1,90 @@
+use itertools::Itertools;
+
 fn main() {
-    println!("Hello, world!");
+    let input = include_str!("../data/input");
+    let input_slice = parse(input);
+    let step1 = brk_enc_step1(&input_slice, 25).unwrap();
+    println!("Step 1: {}", step1);
+    let step2 = brk_enc_step2(&input_slice, *step1).unwrap();
+    println!("Step 2: {}", step2);
 }
+
+fn brk_enc_step1<'a, U>(input: &'a[U], window_size: usize) -> Option<&'a U> where
+    U: PartialEq,
+    &'a U: std::ops::Add<Output = U> {
+        input
+            .windows(window_size + 1)
+            .find(
+                |&w| {
+                    let last = w.last().unwrap();
+                    let firsts = w[..(w.len()-1)].iter().combinations(2);
+                    !firsts.map(|f | {
+                        *f.first().unwrap() + *f.last().unwrap() == *last
+                    }).any(|t|t)
+                }
+            )?.last()
+}
+
+fn brk_enc_step2<'a, U>(input: &'a[U], s1key: U) -> Option<U> where
+    U: PartialEq + std::cmp::Ord + std::iter::Sum<&'a U>,
+    &'a U: std::ops::Add<Output = U> {
+        (2..input.len())
+            .find_map(|x| {
+                input
+                    .windows(x)
+                    .find_map(|w| {
+                        if w.iter().sum::<U>() == s1key {
+                            Some(w.iter().min().unwrap() + w.iter().max().unwrap())
+                        } else {
+                            None
+                        }
+                })
+            })
+            //     (input)
+            // .find(|w| {
+            //     w.sum() == s1key
+            // })
+}
+
+fn parse(input: &'static str) -> Vec<i64> {
+    input
+        .lines()
+        .map(|l| l.parse::<i64>().unwrap())
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    static INPUT: &str = r"35
+20
+15
+25
+47
+40
+62
+55
+65
+95
+102
+117
+150
+182
+127
+219
+299
+277
+309
+576";
+
+    #[test]
+    fn test_step1() {
+        assert_eq!(brk_enc_step1(&parse(INPUT), 5), Some(&127));
+    }
+
+    #[test]
+    fn test_step2() {
+        let a = brk_enc_step2(&parse(INPUT), 127i64).unwrap();
+        assert_eq!(a, 62);
+    }
+}