day 07 pt 1

aoc2023/src/day07.rs

@@ -1,13 +1,67 @@
+use std::cmp::Ordering;
+use std::collections::{HashMap};
+use std::iter::zip;
 use shared::{Solution, Answer};
 
 pub struct Day07;
 
 impl Solution for Day07 {
     fn part_1(&self, input: &str) -> Answer {
-        Answer::Unimplemented
+        let lines: Vec<&str> = input.split("\n").collect();
+        let mut hands: Vec<(&str, u64)> = lines.iter().map(|l|
+            {
+                let x = l.split(" ").collect::<Vec<&str>>();
+                (x[0], x[1].parse::<u64>().unwrap())
+            }
+        ).collect();
+
+        hands.sort_by(compare);
+
+        let res: u64 = hands.iter()
+            .enumerate()
+            .map(|(i, (hand, bet))| ((i+1) as u64) * bet
+            ).sum();
+
+        Answer::from(res)
     }
 
     fn part_2(&self, input: &str) -> Answer {
         Answer::Unimplemented
     }
 }
+
+fn compare(hand1: &(&str, u64), hand2: &(&str, u64)) -> Ordering {
+    let mut s: HashMap<char, u64> = HashMap::new();
+    let mut o: HashMap<char, u64> = HashMap::new();
+
+    for c in hand1.0.chars() {
+        s.insert(c, match s.get(&c) {
+            Some(v) => v+1,
+            None => 1
+        });
+    }
+
+    for c in hand2.0.chars() {
+        o.insert(c, match o.get(&c) {
+            Some(v) => v+1,
+            None => 1
+        });
+    }
+
+    if ( s.keys().count() < o.keys().count() ) |
+        ( s.values().max() > o.values().max() ) { return Ordering::Greater }
+    else if ( s.keys().count() > o.keys().count() ) |
+        ( s.values().max() < o.values().max() ) { return Ordering::Less }
+
+    let ordering = vec!['A', 'K', 'Q', 'J', 'T', '9', '8', '7', '6', '5', '4', '3', '2'];
+
+    for (i, j) in zip(hand1.0.chars(), hand2.0.chars()) {
+        if ordering.iter().position(|&x| x==i) < ordering.iter().position(|&x| x==j) {
+            return Ordering::Greater
+        } else if ordering.iter().position(|&x| x==i) > ordering.iter().position(|&x| x==j) {
+            return Ordering::Less
+        }
+    }
+
+    return Ordering::Equal
+}