Day 7 complete.

src/day7.rs

@@ -0,0 +1,194 @@
+use std::cmp::Ordering;
+use std::collections::HashMap;
+use std::io;
+use std::iter::zip;
+
+fn get_rank(hand: &String) -> u32 {
+  let mut map: HashMap<char, u32> = HashMap::new();
+  for c in hand.chars() {
+    if map.contains_key(&c) {
+      *map.get_mut(&c).unwrap() += 1;
+    } else {
+      map.insert(c, 1);
+    }
+  }
+
+  // Five of a kind
+  for (_, v) in &map {
+    if *v == 5 {
+      return 7;
+    }
+  }
+
+  // Four of a kind
+  for (_, v) in &map {
+    if *v == 4 {
+      return 6;
+    }
+  }
+
+  // Full house & Three of a kind
+  for (_, v) in &map {
+    if *v == 3 {
+      for (_, v2) in &map {
+        if *v2 == 2 {
+          // Full House
+          return 5;
+        }
+      }
+      // Three of a kind
+      return 4;
+    }
+  }
+
+  // Pairs
+  let mut pair_cnt = 0;
+  for (_, v) in &map {
+    if *v == 2 {
+      pair_cnt += 1;
+    }
+  }
+
+  match pair_cnt {
+    2 => 3,
+    1 => 2,
+    _ => 1,
+  }
+}
+
+fn get_rank_wild(hand: &String) -> u32 {
+  let mut map: HashMap<char, u32> = HashMap::new();
+  for c in hand.chars() {
+    if map.contains_key(&c) {
+      *map.get_mut(&c).unwrap() += 1;
+    } else {
+      map.insert(c, 1);
+    }
+  }
+
+  let wild = match map.get(&'J') {
+    Some(v) => *v,
+    None => 0,
+  };
+
+  map.remove(&'J');
+
+  if wild == 5 {
+    return 7;
+  }
+
+  // Five of a kind
+  for (_, v) in &map {
+    if *v + wild == 5 {
+      return 7;
+    }
+  }
+
+  // Four of a kind
+  for (_, v) in &map {
+    if *v + wild == 4 {
+      return 6;
+    }
+  }
+
+  // Natural Full house & Three of a kind
+  for (_, v) in &map {
+    if *v == 3 {
+      for (_, v2) in &map {
+        if *v2 == 2 {
+          // Full House
+          return 5;
+        }
+      }
+      // Three of a kind
+      return 4;
+    }
+  }
+
+  // Pairs
+  let mut pair_cnt = 0;
+  for (_, v) in &map {
+    if *v == 2 {
+      pair_cnt += 1;
+    }
+  }
+
+  match pair_cnt {
+    2 => match wild {
+      1 => 5, // Full House
+      _ => 3, // Two Pair
+    },
+    1 => match wild {
+      1 => 4, // Three of a kind.
+      _ => 2, // One Pair.
+    },
+    _ => match wild {
+      2 => 4, // Three of a kind.
+      1 => 2, // Pair.
+      _ => 1, // High card.
+    },
+  }
+}
+
+fn cmp_card(first: &char, second: &char, jacks_wild: bool) -> Ordering {
+  let order = if jacks_wild {
+    "J23456789TQKA"
+  } else {
+    "23456789TJQKA"
+  };
+  order
+    .find(*first)
+    .unwrap()
+    .cmp(&order.find(*second).unwrap())
+}
+
+fn sort_hands_internal(first: &String, second: &String, jacks_wild: bool) -> Ordering {
+  if jacks_wild {
+    match get_rank_wild(&first).cmp(&get_rank_wild(&second)) {
+      Ordering::Less => return Ordering::Less,
+      Ordering::Greater => return Ordering::Greater,
+      _ => {}
+    }
+  } else {
+    match get_rank(&first).cmp(&get_rank(&second)) {
+      Ordering::Less => return Ordering::Less,
+      Ordering::Greater => return Ordering::Greater,
+      _ => {}
+    }
+  }
+
+  for (f, s) in zip(first.chars(), second.chars()) {
+    match cmp_card(&f, &s, jacks_wild) {
+      Ordering::Less => return Ordering::Less,
+      Ordering::Greater => return Ordering::Greater,
+      _ => {}
+    }
+  }
+
+  Ordering::Equal
+}
+
+fn sort_hands(first: &(String, u64), second: &(String, u64), jacks_wild: bool) -> Ordering {
+  sort_hands_internal(&first.0, &second.0, jacks_wild)
+}
+
+pub fn get_total_winnings(jacks_wild: bool) -> u64 {
+  let mut buffer = String::new();
+  let mut hands: Vec<(String, u64)> = Vec::new();
+  while io::stdin().read_line(&mut buffer).unwrap() > 0 {
+    let mut parts = buffer.trim().split(' ');
+    let hand = parts.next().unwrap();
+    let bidstr = parts.next().unwrap();
+    let bid: u64 = bidstr.parse().expect("Couldn't parse bid");
+    hands.push((hand.to_string(), bid));
+    buffer = String::new();
+  }
+
+  hands.sort_by(|a, b| sort_hands(a, b, jacks_wild));
+
+  let mut score = 0;
+  for i in 0..hands.len() {
+    score += (i as u64 + 1) * hands[i].1;
+  }
+  score
+}

src/main.rs

@@ -6,6 +6,7 @@ mod day3;
 mod day4;
 mod day5;
 mod day6;
+mod day7;
 
 fn main() {
   let args: Vec<String> = env::args().collect();
@@ -26,6 +27,8 @@ fn main() {
     "day5b" => println!("Min: {}", day5::get_lowest_location(true)),
     "day6a" => println!("Product: {}", day6::get_winning_combos()),
     "day6b" => println!("Product: {}", day6::get_single_winning_combo()),
+    "day7a" => println!("Score: {}", day7::get_total_winnings(false)),
+    "day7b" => println!("Score: {}", day7::get_total_winnings(true)),
     _ => println!("Unrecognized day: {}", args[1]),
   }
 }