Update docs on Sat Dec 28 11:02:25 UTC 2024

github-actions[bot] · github-actions[bot] · commit 5ef7b2138e5f · 2024-12-28T11:02:25.000Z
diff --git a/2024/22/index.html b/2024/22/index.html
@@ -302,7 +302,8 @@ <h2 id="problem-name">Monkey Market</h2>
     public object PartTwo(string input) {
         // create a dictionary of all buying options then select the one with the most banana:
 
-        var buyingOptions = new Dictionary&lt;string, int&gt;();
+        var buyingOptions = new Dictionary&lt;(int,int,int,int), int&gt;();
+
         foreach (var num in GetNums(input)) {
             var optionsBySeller = BuyingOptions(num);
             foreach (var seq in optionsBySeller.Keys) {
@@ -312,22 +313,21 @@ <h2 id="problem-name">Monkey Market</h2>
         return buyingOptions.Values.Max();
     }
 
-    Dictionary&lt;string, int&gt; BuyingOptions(int seed) {
+    Dictionary&lt;(int,int,int,int), int&gt; BuyingOptions(int seed) {
         var bananasSold = Bananas(seed).ToArray();
-
-        var buyOptions = new Dictionary&lt;string, int&gt;();
+        var buyingOptions = new Dictionary&lt;(int,int,int,int), int&gt;();
 
         // a sliding window of 5 elements over the sold bananas defines the sequence the monkey 
-        // will recognize. add the first occurrence of each sequence to the buyOptions dictionary 
+        // will recognize. add the first occurrence of each sequence to the buyingOptions dictionary 
         // with the corresponding banana count
-        for (var i = 0; i &lt;= bananasSold.Length - 5; i++) {
-            var slice = bananasSold[i..(i + 5)];
-            var seq = string.Join(&quot;,&quot;, Diff(slice));
-            if (!buyOptions.ContainsKey(seq)) {
-                buyOptions[seq] = slice.Last();
+        var diff = Diff(bananasSold);
+        for (var i = 0; i &lt; bananasSold.Length - 4; i++) {
+            var seq = (diff[i], diff[i+1], diff[i+2], diff[i+3]);
+            if (!buyingOptions.ContainsKey(seq)) {
+                buyingOptions[seq] = bananasSold[i+4];
             }
         }
-        return buyOptions;
+        return buyingOptions;
     }
     int[] Bananas(int seed) =&gt; SecretNumbers(seed).Select(n =&gt; n % 10).ToArray();
 
diff --git a/2024/6/index.html b/2024/6/index.html
@@ -294,8 +294,7 @@ <h2 id="problem-name">Guard Gallivant</h2>
 using System.Collections.Immutable;
 using System.Linq;
 using System.Numerics;
-
-using Map = System.Collections.Generic.Dictionary&lt;System.Numerics.Complex, char&gt;;
+using Map = System.Collections.Immutable.ImmutableDictionary&lt;System.Numerics.Complex, char&gt;;
 
 [ProblemName(&quot;Guard Gallivant&quot;)]
 class Solution : Solver {
@@ -310,17 +309,11 @@ <h2 id="problem-name">Guard Gallivant</h2>
 
     public object PartTwo(string input) {
         var (map, start) = Parse(input);
-        var positions = Walk(map, start).positions;
-        var loops = 0;
-        // simply try a blocker in each locations visited by the guard and count the loops
-        foreach (var block in positions.Where(pos =&gt; map[pos] == &#039;.&#039;)) {
-            map[block] = &#039;#&#039;;
-            if (Walk(map, start).isLoop) {
-                loops++;
-            }
-            map[block] = &#039;.&#039;;
-        }
-        return loops;
+        // try a blocker in each locations visited by the guard counting the loops
+        return Walk(map, start).positions
+                .AsParallel()
+                .Count(pos =&gt; Walk(map.SetItem(pos, &#039;#&#039;), start).isLoop);
+       
     }
 
     // returns the positions visited when starting from &#039;pos&#039;, isLoop is set if the 
@@ -350,7 +343,7 @@ <h2 id="problem-name">Guard Gallivant</h2>
             from y in Enumerable.Range(0, lines.Length)
             from x in Enumerable.Range(0, lines[0].Length)
             select new KeyValuePair&lt;Complex, char&gt;(-Up * y + x, lines[y][x])
-        ).ToDictionary();
+        ).ToImmutableDictionary();
 
         var start = map.First(x =&gt; x.Value == &#039;^&#039;).Key;
         
