day15: added

src/day15/1.rs

@@ -1 +1,42 @@
-const INPUTS: [&'static str; 2] = [include_str!("./sample.txt"), include_str!("./input.txt")];
+#![feature(test)]
+
+extern crate test;
+
+const INPUTS: [&str; 2] = [include_str!("./sample.txt"), include_str!("./input.txt")];
+
+fn process(data: &str) -> usize {
+    let mut answer = 0;
+    let mut current = 0;
+
+    for &c in data.as_bytes() {
+        match c {
+            b',' => {
+                answer += current;
+                current = 0;
+            }
+
+            b'\n' => (),
+            c => {
+                current += c as usize;
+                current *= 17;
+                current %= 256;
+            }
+        }
+    }
+
+    answer + current
+}
+
+fn main() {
+    for input in INPUTS.iter() {
+        println!("answer = {}", process(input));
+    }
+}
+
+#[bench]
+fn part1(b: &mut test::Bencher) {
+    b.iter(|| {
+        let v = process(INPUTS[INPUTS.len() - 1]);
+        test::black_box(v);
+    });
+}

src/day15/2.rs

@@ -1 +1,92 @@
-const INPUTS: [&'static str; 2] = [include_str!("./sample.txt"), include_str!("./input.txt")];
+#![feature(test)]
+
+extern crate test;
+
+const INPUTS: [&str; 2] = [include_str!("./sample.txt"), include_str!("./input.txt")];
+
+fn process(data: &str) -> usize {
+    let mut answer = 0;
+
+    let mut map = vec![vec![]; 256];
+
+    for set in data.as_bytes().split(|&x| x == b',') {
+        let op_idx = set.iter().position(|&x| x == b'=' || x == b'-').unwrap();
+        let bbox = pack(&set[0..op_idx]);
+
+        let op = set[op_idx];
+        let box_id = hash(&set[0..op_idx]);
+
+        match op {
+            b'-' => {
+                let vec = &mut map[box_id];
+
+                if let Some(idx) = vec.iter().position(|(lbox, _)| lbox == &bbox) {
+                    vec.remove(idx);
+                }
+            }
+
+            b'=' => {
+                let lens_focal_length = (set[op_idx + 1] - b'0') as usize;
+
+                if let Some(idx) = map[box_id].iter().position(|(lbox, _)| lbox == &bbox) {
+                    map[box_id][idx] = (bbox, lens_focal_length);
+                } else {
+                    map[box_id].push((bbox, lens_focal_length));
+                }
+            }
+
+            _ => (),
+        }
+    }
+
+    for (box_id, vec) in map.iter().enumerate() {
+        for (j, (_, lens)) in vec.iter().enumerate() {
+            answer += (1 + box_id) * (j + 1) * lens;
+        }
+    }
+
+    answer
+}
+
+#[inline]
+const fn pack(ip: &[u8]) -> u64 {
+    debug_assert!(ip.len() <= 8);
+    let mut out = 0;
+    let mut i = 0;
+
+    while i < ip.len() {
+        out |= ip[i] as u64;
+        out <<= 8;
+        i += 1;
+    }
+
+    out
+}
+
+#[inline]
+const fn hash(ip: &[u8]) -> usize {
+    let mut current: usize = 0;
+    let mut i = 0;
+    while i < ip.len() {
+        let c = ip[i];
+        current += c as usize;
+        current *= 17;
+        current %= 256;
+        i += 1;
+    }
+    current
+}
+
+fn main() {
+    for input in INPUTS.iter() {
+        println!("answer = {}", process(input));
+    }
+}
+
+#[bench]
+fn part2(b: &mut test::Bencher) {
+    b.iter(|| {
+        let v = process(INPUTS[INPUTS.len() - 1]);
+        test::black_box(v);
+    });
+}

src/day15/sample.txt

@@ -0,0 +1 @@
+rn=1,cm-,qp=3,cm=2,qp-,pc=4,ot=9,ab=5,pc-,pc=6,ot=7