From 221cad1136afc53601bbbb58feb83dda9cc49983 Mon Sep 17 00:00:00 2001
From: xeals <dev@xeal.me>
Date: Thu, 7 Dec 2023 17:10:52 +1100
Subject: [PATCH] unwashed day07

---
 src/day07.zig | 61 ++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 56 insertions(+), 5 deletions(-)

diff --git a/src/day07.zig b/src/day07.zig
index 968d416..6cb0a28 100644
--- a/src/day07.zig
+++ b/src/day07.zig
@@ -4,7 +4,7 @@ const mem = std.mem;
 
 pub fn main() !void {
     const input = @embedFile("data/day07.txt");
-    const sln = try solve(util.gpa, input);
+    const sln = try solve2(util.gpa, input);
     std.debug.print("{d}\n", .{sln.a});
     std.debug.print("{d}\n", .{sln.b});
 }
@@ -38,9 +38,9 @@ fn fixCards(cards: *[5]u8) void {
             'A' => 13,
             'K' => 12,
             'Q' => 11,
-            'J' => 10,
+            'J' => 0,
             'T' => 9,
-            '2'...'9' => card - '2',
+            '2'...'9' => card - '1',
             else => unreachable,
         };
     }
@@ -67,6 +67,29 @@ fn scoreHand(cards: Cards) Score {
     };
 }
 
+const joker = 0;
+
+fn scoreHand2(cards: Cards) Score {
+    var jokers: usize = 0;
+    var dups: [14]u8 = undefined;
+    @memset(&dups, 0);
+    for (cards) |a| {
+        if (a == joker) {
+            jokers += 1;
+        } else {
+            dups[a] += 1;
+        }
+    }
+    std.mem.sort(u8, &dups, {}, u8gt);
+    return switch (dups[0] + jokers) {
+        5 => .fiveKind,
+        4 => .fourKind,
+        3 => if (dups[1] == 2) .fullHouse else .threeKind,
+        2 => if (dups[1] == 2) .twoPair else .onePair,
+        else => .high,
+    };
+}
+
 fn compareHand(context: void, a: Hand, b: Hand) bool {
     _ = context;
     if (a.score != b.score) {
@@ -111,6 +134,34 @@ fn solve(alloc: mem.Allocator, input: []const u8) !Solution {
     return .{ .a = partA, .b = 0 };
 }
 
+fn solve2(alloc: mem.Allocator, input: []const u8) !Solution {
+    var hands = try std.ArrayList(Hand).initCapacity(alloc, 1001);
+    defer hands.deinit();
+
+    var it = util.splitLines(input);
+    while (it.next()) |line| {
+        if (line.len == 0) continue;
+
+        var cards = line[0..5].*;
+        fixCards(&cards);
+        const bid = try std.fmt.parseInt(u32, line[6..], 10);
+        const score = scoreHand2(cards);
+        const hand = Hand{ .cards = cards, .bid = bid, .score = score };
+        try hands.append(hand);
+    }
+
+    // std.debug.print("{any}\n", .{hands.items});
+    try sortHands(&hands);
+
+    var partB: usize = 0;
+    for (hands.items, 1..) |hand, rank| {
+        // std.debug.print("{d} * {d}\n", .{ hand.bid, rank });
+        partB += hand.bid * rank;
+    }
+
+    return .{ .a = 0, .b = partB };
+}
+
 test "silver" {
     const input =
         \\32T3K 765
@@ -131,6 +182,6 @@ test "gold" {
         \\KTJJT 220
         \\QQQJA 483
     ;
-    const sln = try solve(std.testing.allocator, input);
-    try std.testing.expectEqual(@as(usize, 0), sln.b);
+    const sln = try solve2(std.testing.allocator, input);
+    try std.testing.expectEqual(@as(usize, 5905), sln.b);
 }