Index: aoc2024.c
==================================================================
--- aoc2024.c
+++ aoc2024.c
@@ -4,36 +4,52 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "aocdailies.h"
 #include "aocutils.h"
+
+static const unsigned *vfind(unsigned v, const unsigned *a, size_t n) {
+    for (size_t k = 0; k < n; k++) {
+        if (a[k] == v) return a + k;
+    }
+    return NULL;
+}
 
 void aoc202405(char *data, size_t len) {
     (void)len; // unused argument
     unsigned pagepair[1200][2], npp = 0; // 1200 works for me
     char *line = strtok(data, "\n");
     while (strchr(line, '|')) {
         char *err;
         pagepair[npp][0] = strtoul(line, &err, 10);
         err += 1; // skip '|'
-        pagepair[npp][1] = strtoul(line, &err, 10);
+        pagepair[npp][1] = strtoul(err, &err, 10);
         npp++;
         line = strtok(NULL, "\n");
     }
-    unsigned update[32], nupdates, maxupdates = 0; // 32 works dor me
-    while ((line = strtok(NULL, "\n")) != NULL) {
+    unsigned update[32], nupdates; // 32 works for me
+    unsigned accumsum = 0;
+    do {
         nupdates = 0;
         char *err = line;
         for (;;) {
             update[nupdates++] = strtoul(err, &err, 10);
             if (*err == ',') err++;
             else break;
         }
-        for (size_t k = 0; k < nupdates; k++) {
-            //...
+        if (nupdates % 2 == 0) printf("even number of updates found!\n");
+        unsigned accumulate = update[nupdates / 2];
+        for (size_t k = 0; k < npp; k++) {
+            const unsigned *before = vfind(pagepair[k][0], update, nupdates);
+            if (!before) continue;
+            const unsigned *after = vfind(pagepair[k][1], update, nupdates);
+            if (!after) continue;
+            if (before > after) { accumulate = 0; break; }
         }
-    }
+        accumsum += accumulate;
+    } while ((line = strtok(NULL, "\n")) != NULL);
+    printf("The sum of middle update numbers is {%u}\n", accumsum);
 }
 
 static size_t rcmap(unsigned size, unsigned row, unsigned col) {
     return row * (size + 1) + col;
 }