Day5

day5/rust/src/main.rs

@@ -0,0 +1,74 @@
+use std::{cmp::Ordering, io::Read};
+
+use itertools::Itertools;
+
+struct Rule {
+    first: isize,
+    second: isize,
+}
+
+fn main() {
+    let mut stdin = std::io::stdin();
+
+    let mut input = String::new();
+    stdin.read_to_string(&mut input).unwrap();
+
+    let (rules_string, updates_string) = input.split("\n\n").collect_tuple().unwrap();
+
+    let rules: Vec<_> = rules_string
+        .split("\n")
+        .filter(|e| e.len() > 0)
+        .map(|e| {
+            e.split("|")
+                .map(|e| e.parse().unwrap())
+                .collect_tuple::<(isize, isize)>()
+                .unwrap()
+        })
+        .map(|e| Rule {
+            first: e.0,
+            second: e.1,
+        })
+        .collect();
+
+    let updates: Vec<_> = updates_string
+        .split("\n")
+        .filter(|e| e.len() > 0)
+        .map(|e| {
+            e.split(",")
+                .map(|e| e.parse().unwrap())
+                .collect::<Vec<isize>>()
+        })
+        .collect();
+
+    let mut count = 0;
+    let mut count2 = 0;
+    updates.iter().for_each(|update| {
+        let mut sorted = update.clone();
+        sorted.sort_by(|&a, &b| {
+            if let Some(_) = rules
+                .iter()
+                .find(|rule| rule.first == a && rule.second == b)
+            {
+                return Ordering::Less;
+            }
+
+            if let Some(_) = rules
+                .iter()
+                .find(|rule| rule.second == a && rule.first == b)
+            {
+                return Ordering::Greater;
+            }
+
+            return Ordering::Equal;
+        });
+
+        if sorted == *update {
+            count += update[update.len() / 2];
+        } else {
+            count2 += sorted[update.len() / 2];
+        }
+    });
+
+    println!("{}", count);
+    println!("{}", count2);
+}