diff --git a/2022/inputs/day11 b/2022/inputs/day11
new file mode 100644
index 0000000..0a6a52e
--- /dev/null
+++ b/2022/inputs/day11
@@ -0,0 +1,55 @@
+Monkey 0:
+  Starting items: 96, 60, 68, 91, 83, 57, 85
+  Operation: new = old * 2
+  Test: divisible by 17
+    If true: throw to monkey 2
+    If false: throw to monkey 5
+
+Monkey 1:
+  Starting items: 75, 78, 68, 81, 73, 99
+  Operation: new = old + 3
+  Test: divisible by 13
+    If true: throw to monkey 7
+    If false: throw to monkey 4
+
+Monkey 2:
+  Starting items: 69, 86, 67, 55, 96, 69, 94, 85
+  Operation: new = old + 6
+  Test: divisible by 19
+    If true: throw to monkey 6
+    If false: throw to monkey 5
+
+Monkey 3:
+  Starting items: 88, 75, 74, 98, 80
+  Operation: new = old + 5
+  Test: divisible by 7
+    If true: throw to monkey 7
+    If false: throw to monkey 1
+
+Monkey 4:
+  Starting items: 82
+  Operation: new = old + 8
+  Test: divisible by 11
+    If true: throw to monkey 0
+    If false: throw to monkey 2
+
+Monkey 5:
+  Starting items: 72, 92, 92
+  Operation: new = old * 5
+  Test: divisible by 3
+    If true: throw to monkey 6
+    If false: throw to monkey 3
+
+Monkey 6:
+  Starting items: 74, 61
+  Operation: new = old * old
+  Test: divisible by 2
+    If true: throw to monkey 3
+    If false: throw to monkey 1
+
+Monkey 7:
+  Starting items: 76, 86, 83, 55
+  Operation: new = old + 4
+  Test: divisible by 5
+    If true: throw to monkey 4
+    If false: throw to monkey 0
diff --git a/2022/src/bin/day11.rs b/2022/src/bin/day11.rs
new file mode 100644
index 0000000..a2d0ac3
--- /dev/null
+++ b/2022/src/bin/day11.rs
@@ -0,0 +1,134 @@
+#![feature(test)]
+extern crate test;
+use aoc2022::{boilerplate, common::*};
+
+const DAY: usize = 11;
+type Parsed = Vec<Monkey>;
+
+#[derive(Clone, Debug)]
+struct Monkey {
+    inspection_count: usize,
+    items:            Vec<usize>,
+    op:               MonkeyOp,
+    div_test:         usize,
+    true_dst:         usize,
+    false_dst:        usize,
+}
+
+#[derive(Copy, Clone, Debug)]
+enum MonkeyOp {
+    Add(Option<usize>, Option<usize>),
+    Mul(Option<usize>, Option<usize>),
+}
+
+fn parse_input(raw: &str) -> Parsed {
+    raw.split("\n\n")
+        .map(|raw_monkey| {
+            let mut lines = raw_monkey.lines();
+            let [_, start, op, test, if_true, if_false] = std::array::from_fn(|_| lines.next().unwrap());
+            let items = start[18..].split(", ").map(parse_num).collect();
+            let div_test = parse_num(&test[21..]);
+            let true_dst = parse_num(&if_true[29..]);
+            let false_dst = parse_num(&if_false[30..]);
+            let op = match op[19..].split(' ').collect::<Vec<_>>().as_slice() {
+                [x, "+", y] => MonkeyOp::Add(x.parse().ok(), y.parse().ok()),
+                [x, "*", y] => MonkeyOp::Mul(x.parse().ok(), y.parse().ok()),
+                _ => unreachable!(),
+            };
+            Monkey { inspection_count: 0, items, op, div_test, true_dst, false_dst }
+        })
+        .collect()
+}
+
+// Stolen from my 2019 day 12 solution
+fn lcm(x: usize, y: usize) -> usize {
+    fn gcd(mut x: usize, mut y: usize) -> usize {
+        let mut remainder;
+        while y != 0 {
+            remainder = x % y;
+            x = y;
+            y = remainder;
+        }
+        x
+    }
+    x * y / gcd(x, y)
+}
+
+fn part1(parsed: &Parsed) -> usize {
+    monkey_business::<20, 3>(parsed)
+}
+
+fn part2(parsed: &Parsed) -> usize {
+    monkey_business::<10_000, 1>(parsed)
+}
+
+fn monkey_business<const ITERATIONS: usize, const STRESS_REDUCTION: usize>(parsed: &Parsed) -> usize {
+    let lcm = parsed.iter().map(|m| m.div_test).reduce(lcm).unwrap();
+    println!("lcm: {lcm}");
+    let mut monkeys: Vec<Monkey> = parsed.clone();
+    let mut moved = Vec::new();
+    for _ in 0..ITERATIONS {
+        let mut i = 0;
+        while i < monkeys.len() {
+            let monkey = monkeys.get_mut(i).unwrap();
+            monkey.inspection_count += monkey.items.len();
+            while !monkey.items.is_empty() {
+                moved.extend(monkey.items.drain(..).map(|mut stress| {
+                    stress = match monkey.op {
+                        MonkeyOp::Add(x, y) => x.unwrap_or(stress) + y.unwrap_or(stress),
+                        MonkeyOp::Mul(x, y) => x.unwrap_or(stress) * y.unwrap_or(stress),
+                    } / STRESS_REDUCTION;
+                    if stress > lcm {
+                        stress %= lcm;
+                    }
+                    (stress, if stress % monkey.div_test == 0 { monkey.true_dst } else { monkey.false_dst })
+                }));
+            }
+            drop(monkey);
+            for (item, dst) in moved.drain(..) {
+                monkeys.get_mut(dst).unwrap().items.push(item);
+            }
+            i += 1;
+        }
+    }
+    monkeys.sort_by_key(|m| m.inspection_count);
+    monkeys.into_iter().rev().map(|m| m.inspection_count).take(2).product()
+}
+
+boilerplate! {
+    TEST_INPUT == "\
+Monkey 0:
+  Starting items: 79, 98
+  Operation: new = old * 19
+  Test: divisible by 23
+    If true: throw to monkey 2
+    If false: throw to monkey 3
+
+Monkey 1:
+  Starting items: 54, 65, 75, 74
+  Operation: new = old + 6
+  Test: divisible by 19
+    If true: throw to monkey 2
+    If false: throw to monkey 0
+
+Monkey 2:
+  Starting items: 79, 60, 97
+  Operation: new = old * old
+  Test: divisible by 13
+    If true: throw to monkey 1
+    If false: throw to monkey 3
+
+Monkey 3:
+  Starting items: 74
+  Operation: new = old + 3
+  Test: divisible by 17
+    If true: throw to monkey 0
+    If false: throw to monkey 1",
+    tests: {
+        part1: { TEST_INPUT => 10605 },
+        part2: { TEST_INPUT => 2713310158 },
+    },
+    bench1 == 56595,
+    bench2 == 15693274740,
+    bench_parse: Vec::len => 8,
+}