Index: aoc2024.c
==================================================================
--- aoc2024.c
+++ aoc2024.c
@@ -4,10 +4,13 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include "aocdailies.h"
 #include "aocutils.h"
+
+static void reorder(unsigned *a, size_t na, unsigned (*r)[2], size_t nr) {
+}
 
 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;
     }
@@ -35,21 +38,28 @@
             update[nupdates++] = strtoul(err, &err, 10);
             if (*err == ',') err++;
             else break;
         }
         if (nupdates % 2 == 0) printf("even number of updates found!\n");
-        unsigned accumulate = update[nupdates / 2];
+        unsigned accum = update[nupdates / 2], accumsum2 = 0;
         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; }
+            if (before > after) {
+                accum = 0;
+                // reorder `update` according to `pagepair`
+                reorder(update, nupdates, pagepair, npp);
+                accumsum2 += update[nupdates / 2];
+                break;
+            }
         }
-        accumsum += accumulate;
+        accumsum += accum;
     } while ((line = strtok(NULL, "\n")) != NULL);
     printf("The sum of middle update numbers is {%u}\n", accumsum);
+    printf("The sum of middle update numbers for newly ordered updates is {%u}\n", accumsum2);
 }
 
 static size_t rcmap(unsigned size, unsigned row, unsigned col) {
     return row * (size + 1) + col;
 }