Day7 part1

day7/Cargo.lock

@@ -0,0 +1,16 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "anyhow"
+version = "1.0.75"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4668cab20f66d8d020e1fbc0ebe47217433c1b6c8f2040faf858554e394ace6"
+
+[[package]]
+name = "day7"
+version = "0.1.0"
+dependencies = [
+ "anyhow",
+]

day7/Cargo.toml

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+[package]
+name = "day7"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+anyhow = "1.0.75"

day7/src/main.rs

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+use std::{fmt::Display, io::stdin, str::FromStr};
+use anyhow::{anyhow, Result, Error};
+
+#[derive(Debug,Clone,Copy,Eq,PartialEq)]
+struct Card(char);
+
+#[derive(Debug,Clone,Copy,Eq,PartialEq)]
+struct Hand([Card; 5]);
+
+#[derive(Debug,Clone,Copy,Eq,PartialEq,Ord,PartialOrd)]
+enum Suit {
+    HighCard,
+    OnePair,
+    TwoPairs,
+    Three,
+    Full,
+    Four,    
+    Five,
+}
+
+impl Card {
+
+    fn new(c: char) -> Result<Self> {
+        match c {
+            'A'|'K'|'Q'|'J'|'T'|'2'..='9' => Ok(Self(c)),
+            _ => Err(anyhow!("invalid card {c:?}"))
+        }
+    }
+
+    fn value(self) -> usize {
+        match self.0 {
+            'A' => 14,
+            'K' => 13,
+            'Q' => 12,
+            'J' => 11,
+            'T' => 10,
+            '2'..='9' => char::to_digit(self.0, 10).unwrap() as usize,
+            _ => panic!("invalid card"),
+        }
+    }
+}
+
+impl Ord for Card {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        self.value().cmp(&other.value())
+    }
+}
+
+impl PartialOrd for Card {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        Some(self.0.cmp(&other.0))
+    }
+}
+
+impl Display for Card {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl Hand {
+    fn suit(&self) -> Suit {
+        let mut cache = [0; 16];
+        let mut counts = [0; 5];
+        for v in self.0 {
+            cache[v.value()] += 1;
+        }
+        for c in cache {
+            if c > 0 { counts[c-1] += 1 }
+        }
+        
+        match counts {
+            [_,_,_,_,1] => Suit::Five,
+            [_,_,_,1,_] => Suit::Four,
+            [_,1,1,_,_] => Suit::Full,
+            [_,_,1,_,_] => Suit::Three,
+            [_,2,_,_,_] => Suit::TwoPairs,
+            [_,1,_,_,_] => Suit::OnePair,
+            _ => Suit::HighCard,
+        }
+    }
+}
+
+impl Ord for Hand {
+    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
+        self.suit().cmp(&other.suit())
+            .then_with(|| self.0.cmp(&other.0))
+    }
+}
+
+impl PartialOrd for Hand {
+    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+        Some(self.cmp(&other))
+    }
+}
+
+impl FromStr for Hand {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        if s.len() != 5 { return Err(anyhow!("Invalid hand {s}")) }
+        let c = s.chars().map(Card::new)
+            .collect::<Result<Vec<_>>>()?;
+
+        Ok(Self([c[0], c[1], c[2], c[3], c[4]]))
+    }
+}
+
+fn main() -> Result<()> {
+    
+    let mut data: Vec<(Hand, usize)> = stdin()
+        .lines()
+        .map(|l| -> Result<(Hand,usize)> {
+            let l = l?;
+            let (hand, bet) = l.split_once(' ')
+                .ok_or_else(|| anyhow!("bad line {l:?}"))?;
+            Ok((hand.parse()?, bet.parse()?))
+        })
+        .collect::<Result<_>>()?;
+        
+    data.sort_by(|a,b| a.0.cmp(&b.0));
+
+    let total: usize = data.iter()
+        .enumerate()
+        .map(|(rank, (_,bid))| bid*(rank+1) )
+        .sum();
+
+    println!("Part 1: total winnings {total}");
+
+    Ok(())
+
+}

day7/test

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+32T3K 765
+T55J5 684
+KK677 28
+KTJJT 220
+QQQJA 483