advent2024

commit 4724c41ca54f72dc21df59ecf3c957c8043c585e
parent a050f700e90dfd22421196e357639af4dc8a52a0
Author: bsandro <email@bsandro.tech>
Date:   Thu, 12 Dec 2024 02:28:02 +0200

Day 11 p2 slightly less puke-inducing

Diffstat:
M
day11/main.cpp
 | 
23
+++++------------------

1 file changed, 5 insertions(+), 18 deletions(-)
diff --git a/day11/main.cpp b/day11/main.cpp
@@ -28,32 +28,19 @@ T read_file(const std::string &path) {
 
 typedef std::tuple<int, uint64_t, uint64_t> Memo;
 typedef std::map<uint64_t, Memo> Cache;
-typedef std::map<uint64_t, std::vector<std::pair<int, uint64_t>>> GenCache;
-
-uint64_t findGenCache(GenCache &cache, uint64_t stone, int num) {
-    uint64_t val = 0;
-    for (auto v:cache[stone]) {
-        auto [blinks, sum] = v;
-        if (blinks==num) {
-            val=sum;
-            break;
-        }
-    }
-    return val;
-}
+typedef std::map<std::pair<uint64_t, int>, uint64_t> GenCache;
 
 uint64_t calc(uint64_t stone, int num, Cache &cache, GenCache &genCache) {
     if (num<=0) return 1;
-    if (genCache.contains(stone)) {
-        uint64_t v = findGenCache(genCache, stone, num);
-        if (v!=0) return v;
+    if (genCache.contains(std::make_pair(stone, num))) {
+        return genCache[std::make_pair(stone, num)];
     }
     if (cache.contains(stone)) {
         auto [blinks, s1, s2] = cache[stone];
         if (blinks>num) return 1;
         else if (s1==0) return 1;
         uint64_t res = calc(s1, num-blinks, cache, genCache)+calc(s2, num-blinks, cache, genCache);
-        genCache[stone].push_back(std::make_pair(num, res));
+        genCache[std::make_pair(stone, num)] = res;
         return res;
     }
 
@@ -71,7 +58,7 @@ uint64_t calc(uint64_t stone, int num, Cache &cache, GenCache &genCache) {
             derived *= 2024;
         }
     }
-    genCache[stone].push_back(std::make_pair(num, 1));
+    genCache[std::make_pair(stone, num)] = 1;
     return 1;
 }