3 files changed, 116 insertions, 0 deletions

diff --git a/2022/11/a.rs b/2022/11/a.rs
new file mode 100644
index 0000000..0d0de04
--- /dev/null
+++ b/2022/11/a.rs
@@ -0,0 +1,7 @@
+mod common;
+use common::*;
+
+fn main() {
+    let mut monkeys = read_input();
+    println!("{}", res_after_n_rounds(&mut monkeys, 20, 3));
+}
diff --git a/2022/11/b.rs b/2022/11/b.rs
new file mode 100644
index 0000000..7886522
--- /dev/null
+++ b/2022/11/b.rs
@@ -0,0 +1,7 @@
+mod common;
+use common::*;
+
+fn main() {
+    let mut monkeys = read_input();
+    println!("{}", res_after_n_rounds(&mut monkeys, 10000, 1));
+}
diff --git a/2022/11/common.rs b/2022/11/common.rs
new file mode 100644
index 0000000..68a379a
--- /dev/null
+++ b/2022/11/common.rs
@@ -0,0 +1,102 @@
+#[derive(Debug)]
+pub struct Monkey {
+    items: Vec<i64>,
+    op: fn(i64, i64) -> i64,
+    oparg: i64,
+    div: i64,
+    iftrue: usize,
+    iffalse: usize,
+    pub inspected: usize
+}
+
+fn read_monkey_from_stdin() -> Monkey {
+    let mut line = String::new();
+    let stdin = std::io::stdin();
+
+    let _ = stdin.read_line(&mut line);
+    line.clear();
+
+    let _ = stdin.read_line(&mut line);
+    let mut l = 16;
+    let mut items = Vec::<i64>::new();
+    while line.chars().nth(l).unwrap() != '\n' {
+        l += 2;
+        let end = line[l..].find(|c| c == ',' || c == '\n').unwrap() + l;
+        items.push(line[l..end].parse::<i64>().unwrap());
+        l = end;
+    }
+    line.clear();
+
+    let _ = stdin.read_line(&mut line);
+    let old = line.chars().nth(25).unwrap() == 'o';
+    let oparg = if old { 0 } else {
+        line[25..line.len()-1].parse::<i64>().unwrap()
+    };
+    let op = match line.chars().nth(23).unwrap() {
+        '*' => if old { |x, _| x * x } else { |x, y| x * y },
+        '+' => if old { |x, _| x + x } else { |x, y| x + y },
+        c => panic!("Expected operator, got {}", c)
+    };
+    line.clear();
+
+    let _ = stdin.read_line(&mut line);
+    let div = line[21..line.len()-1].parse::<i64>().unwrap();
+    line.clear();
+
+    let _ = stdin.read_line(&mut line);
+    let iftrue = line[29..line.len()-1].parse::<usize>().unwrap();
+    line.clear();
+
+    let _ = stdin.read_line(&mut line);
+    let iffalse = line[30..line.len()-1].parse::<usize>().unwrap();
+    line.clear();
+
+    Monkey { items, op, oparg, div, iftrue, iffalse, inspected: 0 }
+}
+
+pub fn read_input() -> Vec<Monkey> {
+    let mut v = Vec::<Monkey>::new();
+    let mut line = String::new();
+    loop {
+        v.push(read_monkey_from_stdin());
+        if std::io::stdin().read_line(&mut line).unwrap() == 0 { break; }
+    }
+    v
+}
+
+fn play_round(m: &mut Vec<Monkey>, div: i64, modulus: i64) {
+    for i in 0..m.len() {
+        for k in 0..m[i].items.len() {
+            let mut x = (m[i].op)(m[i].items[k], m[i].oparg) / div;
+            if div == 1 { x %= modulus; }
+            let j = if x % m[i].div == 0 { m[i].iftrue } else { m[i].iffalse };
+            m[j].items.push(x);
+        }
+        m[i].inspected += m[i].items.len();
+        m[i].items.clear();
+    }
+}
+
+fn get_modulus(monkeys: &Vec<Monkey>) -> i64 {
+    let mut modulus = 1;
+    for m in monkeys { modulus *= m.div; }
+    modulus
+}
+
+pub fn res_after_n_rounds(m: &mut Vec<Monkey>, n: usize, div: i64) -> usize {
+    let modulus = get_modulus(&m);
+    for _ in 0..n { play_round(m, div, modulus); }
+
+    let mut m1 = 0;
+    let mut m2 = 0;
+    for m in m {
+        if m.inspected >= m1 {
+            m2 = m1;
+            m1 = m.inspected;
+        } else if m.inspected >= m2 {
+            m2 = m.inspected;
+        }
+    }
+
+    m1 * m2
+}