completed day 7

Author: douglasdennis-pnnl

day7.lua

@@ -0,0 +1,153 @@
+CardValue = {
+    ["A"]=13,
+    ["K"]=12,
+    ["Q"]=11,
+    ["T"]=9,
+    ["9"]=8,
+    ["8"]=7,
+    ["7"]=6,
+    ["6"]=5,
+    ["5"]=4,
+    ["4"]=3,
+    ["3"]=2,
+    ["2"]=1,
+    ["J"]=0,
+}
+
+HandTypeValue = {
+    ["five of a kind"] = 6,
+    ["four of a kind"] = 5,
+    ["full house"] = 4,
+    ["three of a kind"] = 3,
+    ["two pair"] = 2,
+    ["one pair"] = 1,
+    ["high card"] = 0,
+}
+
+function GetHandType(hand)
+    local card_counts = {}
+    for k, _ in pairs(CardValue) do
+        card_counts[k] = 0
+    end
+
+    for i=1,#hand do
+        local card = string.sub(hand, i, i)
+        card_counts[card] = card_counts[card] + 1
+    end
+
+    local max_counts = {0, 0}
+    for card, count in pairs(card_counts) do
+        if card ~= "J" then
+            if count >= max_counts[1] then
+                max_counts[2] = max_counts[1]
+                max_counts[1] = count
+            elseif count > max_counts[2] then
+                max_counts[2] = count
+            end
+        end
+    end
+
+    if card_counts["J"] == 5 or card_counts["J"] == 4 then
+        return "five of a kind"
+    end
+
+    if max_counts[1] == 5 then
+        return "five of a kind"
+    elseif max_counts[1] == 4 then
+        if card_counts["J"] == 1 then
+            return "five of a kind"
+        end
+        return "four of a kind"
+    elseif max_counts[1] == 3 then
+        if card_counts["J"] == 2 then
+            return "five of a kind"
+        elseif card_counts["J"] == 1 then
+            return "four of a kind"
+        elseif max_counts[2] == 2 then
+            return "full house"
+        else
+            return "three of a kind"
+        end
+    elseif max_counts[1] == 2 then
+        if card_counts["J"] == 3 then
+            return "five of a kind"
+        elseif card_counts["J"] == 2 then
+            return "four of a kind"
+        elseif card_counts["J"] == 1 then
+            if max_counts[2] == 2 then
+                return "full house"
+            else
+                return "three of a kind"
+            end
+        elseif max_counts[2] == 2 then
+            return "two pair"
+        else
+            return "one pair"
+        end
+    end
+    if card_counts["J"] == 3 then
+        return "four of a kind"
+    elseif card_counts["J"] == 2 then
+        return "three of a kind"
+    elseif card_counts["J"] == 1 then
+        return "one pair"
+    end
+    return "high card"
+end
+
+function EmbedHands(hands)
+    local embedded_hands = {}
+    for i, hand in pairs(hands) do
+        local hand_type_value = HandTypeValue[GetHandType(hand.cards)]
+        local card_values = {}
+        for value_i=1,5 do
+            card_values[value_i] = CardValue[string.sub(hand.cards, value_i, value_i)]
+        end
+        local hand_embedding =
+         (hand_type_value << 20) |
+         (card_values[1] << 16) |
+         (card_values[2] << 12) |
+         (card_values[3] << 8) |
+         (card_values[4] << 4) |
+         card_values[5]
+        embedded_hands[i] = {cards=hand.cards, value=hand_embedding, bid=hand.bid}
+    end
+    return embedded_hands
+end
+
+function ParseHands()
+    local hands = {}
+    local line = io.read("*l")
+    while line ~= nil do
+        local cards = string.match(line, "(.+) ")
+        local bid = tonumber(string.match(line, " (%d+)"))
+        hands[#hands+1] = {cards=cards, bid=bid}
+        line = io.read("*l")
+    end
+    return hands
+end
+
+function CompareHands(a, b)
+    return a.value < b.value
+end
+
+io.input("day7.in")
+local hands = ParseHands()
+local embedded_hands = EmbedHands(hands)
+table.sort(embedded_hands, CompareHands)
+local total = 0
+local subtotal = 0
+for i, hand in pairs(embedded_hands) do
+    if string.match(hand.cards, "J") then
+        print(i, hand.cards, hand.bid, hand.value, GetHandType(hand.cards))
+    end
+    total = total + hand.bid * i
+end
+
+-- 249748283
+-- 248457642 (too high)
+-- 248581739 (too high)
+-- 248457642 (too high)
+-- 248029057
+print(subtotal)
+print(total)