2023: Day 7, part 1

2023/day7/Cargo.lock

@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "day7"
+version = "0.1.0"

2023/day7/Cargo.toml

@@ -0,0 +1,8 @@
+[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]

2023/day7/Makefile

@@ -0,0 +1,2 @@
+day7: day7.cpp
+	c++ -Wall -fsanitize=address day7.cpp -o day7

2023/day7/compile_commands.json

@@ -0,0 +1,7 @@
+[
+{
+  "directory": "/home/wmoore/Projects/advent-of-code/2023/day7",
+  "command": "c++ -Wall -fsanitize=address day7.cpp -o day7",
+  "file": "day7.cpp"
+}
+]

2023/day7/day7.cpp

@@ -0,0 +1,105 @@
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <string>
+#include <map>
+
+using std::cout, std::cerr, std::endl;
+
+// From strongest to weakest
+enum class Type {
+  // Five of a kind, where all five cards have the same label: AAAAA
+  FiveOfAKind = 7,
+  // Four of a kind, where four cards have the same label and one card has a
+  // different label: AA8AA
+  FourOfAKind = 6,
+  // Full house, where three cards have the same label, and the remaining two
+  // cards share a different label: 23332
+  FullHouse = 5,
+  // Three of a kind, where three cards have the same label, and the remaining
+  // two cards are each different from any other card in the hand: TTT98
+  ThreeOfAKind = 4,
+  // Two pair, where two cards share one label, two other cards share a second
+  // label, and the remaining card has a third label: 23432
+  TwoPair = 3,
+  // One pair, where two cards share one label, and the other three cards have a
+  // different label from the pair and each other: A23A4
+  OnePair = 2,
+  // High card, where all cards' labels are distinct: 23456
+  HighCard = 1,
+  Nothing = 0,
+};
+
+class Hand {
+  Hand(std::string, int);
+
+  Type type();
+
+  std::string hand;
+  int bid;
+};
+
+Hand::Hand(std::string s, int n) : hand{s}, bid{n} {
+  if (hand.length() != 5) {
+    throw "hand length != 5";
+  }
+}
+
+Type Hand::type()  {
+  std::unordered_map<char, int> counts;
+
+  for(auto c : hand) {
+    counts[c] += 1;
+  }
+
+  if (counts.size() == 1) {
+    return Type::FiveOfAKind;
+  }
+  else if (counts.size() == 2) {
+    const auto it{counts.begin()};
+    auto count{it->second};
+    switch (count) {
+      case 1:
+      case 4:
+        return Type::FourOfAKind;
+      case 2:
+      case 3:
+        return Type::FullHouse;
+    }
+
+    for (const auto p : counts) {
+
+    }
+  }
+
+  return Type::Nothing;
+}
+
+int main(int argc, char **argv) {
+  if (argc < 2) {
+    cerr << "Usage: day7 input.txt" << endl;
+    return 1;
+  }
+
+  std::ifstream ifs{argv[1]};
+  std::string input{(std::istreambuf_iterator<char>(ifs)),
+                    (std::istreambuf_iterator<char>())};
+  std::istringstream iss{input};
+
+  for (std::string line; std::getline(iss, line);) {
+    if (line.empty()) {
+      continue;
+    }
+
+    std::istringstream liness{line};
+    std::string hand;
+    int bid;
+
+    liness >> hand >> bid;
+    cout << hand << ": " << bid << endl;
+
+
+  }
+
+  return 0;
+}

2023/day7/src/main.rs

@@ -0,0 +1,116 @@
+use std::cmp::Ordering;
+use std::collections::HashMap;
+use std::{env, fs};
+
+type BoxError = Box<dyn std::error::Error>;
+
+#[derive(Debug, Ord, PartialOrd, Eq, PartialEq, Copy, Clone)]
+enum Type {
+    // Five of a kind, where all five cards have the same label: AAAAA
+    FiveOfAKind = 7,
+    // Four of a kind, where four cards have the same label and one card has a
+    // different label: AA8AA
+    FourOfAKind = 6,
+    // Full house, where three cards have the same label, and the remaining two
+    // cards share a different label: 23332
+    FullHouse = 5,
+    // Three of a kind, where three cards have the same label, and the remaining
+    // two cards are each different from any other card in the hand: TTT98
+    ThreeOfAKind = 4,
+    // Two pair, where two cards share one label, two other cards share a second
+    // label, and the remaining card has a third label: 23432
+    TwoPair = 3,
+    // One pair, where two cards share one label, and the other three cards have a
+    // different label from the pair and each other: A23A4
+    OnePair = 2,
+    // High card, where all cards' labels are distinct: 23456
+    HighCard = 1,
+    Nothing = 0,
+}
+
+#[derive(Debug)]
+struct Hand {
+    hand: String,
+    bid: u32,
+}
+
+fn main() -> Result<(), BoxError> {
+    let input_path = env::args_os()
+        .skip(1)
+        .next()
+        .ok_or("missing input file path")?;
+    let input = fs::read_to_string(input_path)?;
+
+    let mut hands = Vec::new();
+    for line in input.lines() {
+        if line.is_empty() {
+            continue;
+        }
+
+        let (hand, bid) = line.split_once(' ').ok_or("unable to split line")?;
+        hands.push(Hand {
+            hand: hand.to_string(),
+            bid: bid.parse()?,
+        });
+    }
+
+    let mut ranked = hands
+        .iter()
+        .map(|hand| (hand.hand_type(), hand))
+        .collect::<Vec<_>>();
+    ranked.sort_by(|(a_ty, a_hand), (b_ty, b_hand)| match a_ty.cmp(b_ty) {
+        Ordering::Equal => {
+            // println!("tie break {} {}", a_hand.hand, b_hand.hand);
+            for (ach, bch) in a_hand.hand.chars().zip(b_hand.hand.chars()) {
+                let ord = cmp_card(ach, bch);
+                if ord != Ordering::Equal {
+                    return ord;
+                }
+            }
+            // All chars the same
+            return Ordering::Equal;
+        }
+        ord => ord,
+    });
+    let mut total_winnings = 0;
+    for (i, (_ty, hand)) in ranked.iter().enumerate() {
+        // println!("{} * {} = {}", (i as u32 + 1), hand.bid, (i as u32 + 1) * hand.bid);
+        total_winnings += (i as u32 + 1) * hand.bid;
+    }
+
+    // dbg!(&ranked);
+    println!("Part 1: {total_winnings}");
+
+    Ok(())
+}
+
+impl Hand {
+    fn hand_type(&self) -> Type {
+        let mut map = HashMap::with_capacity(5);
+        for c in self.hand.chars() {
+            *map.entry(c).or_insert(0) += 1;
+        }
+        let mut counts = map.values().collect::<Vec<_>>();
+        counts.sort_unstable();
+        counts.reverse();
+        match counts[..] {
+            [5] => Type::FiveOfAKind,
+            [4, 1] => Type::FourOfAKind,
+            [3, 2] => Type::FullHouse,
+            [3, 1, 1] => Type::ThreeOfAKind,
+            [2, 2, 1] => Type::TwoPair,
+            [1, 1, 1, 1, 1] => Type::HighCard,
+            _ if *counts[0] == 2 => Type::OnePair,
+            _ => Type::Nothing,
+        }
+    }
+}
+
+fn cmp_card(a: char, b: char) -> Ordering {
+    let sort = [
+        'A', 'K', 'Q', 'J', 'T', '9', '8', '7', '6', '5', '4', '3', '2',
+    ];
+    let ai = sort.iter().position(|&c| a == c).expect("invalid char");
+    let bi = sort.iter().position(|&c| b == c).expect("invalid char");
+    bi.cmp(&ai)
+}

2023/input/day7.sample

@@ -0,0 +1,6 @@
+32T3K 765
+T55J5 684
+KK677 28
+KTJJT 220
+QQQJA 483
+