Index: aoc2024.c
==================================================================
--- aoc2024.c
+++ aoc2024.c
@@ -22,11 +22,11 @@
             if (ndisk == rdisk) {
                 // assume it works
                 rdisk = (13*rdisk)/8;
                 disk = realloc(disk, rdisk * sizeof *disk);
             }
-            disk[ndisk++] = fileid;
+            disk[ndisk++] = (fileid * 10) + (*data - '0'); // encode fileid and length
         }
         fileid++;
         data++;
         if (*data) {
             for (int k = 0; k < *data - '0'; k++) {
@@ -55,11 +55,11 @@
         *left++ = tmp;
     }
     unsigned long long chksum = 0;
     size_t index = 0;
     while (disk[index] >= 0) {
-        chksum += (size_t)disk[index] * index;
+        chksum += ((size_t)disk[index]/10) * index;
         index++;
     }
     printf("%llu\n", chksum);
     free(disk);