2 files changed, 30 insertions, 1 deletions
diff --git a/2024/aoc-utils.scm b/2024/aoc-utils.scm
index 7fafcc6..98e83cd 100644
--- a/2024/aoc-utils.scm
+++ b/2024/aoc-utils.scm
@@ -15,3 +15,15 @@
   (map (lambda (line)
          (map string->number (string-split line #\Space)))
        lines))
+
+(define (remove-nth l n)
+  "Remove the `N' element from `L', returning a new list."
+  (append (list-head l n) (list-tail l (1+ n))))
+
+(define (indexes lst)
+  "Get the indexes for `lst'."
+  (let ((retval '()))
+    (do ((i (1- (length lst)) (1- i)))
+        ((< i 0))
+      (set! retval (cons i retval)))
+    retval))
diff --git a/2024/day02/main.scm b/2024/day02/main.scm
index 310f72e..07f0a4d 100755
--- a/2024/day02/main.scm
+++ b/2024/day02/main.scm
@@ -38,9 +38,26 @@
                                         1
                                         0)) reports))))
 
+(define (indexes report)
+  (let ((retval '()))
+    (do ((i (1- (length report)) (1- i)))
+        ((< i 0))
+      (set! retval (cons i retval)))
+    retval))
+
+(define (gen-reports report)
+  (cons report (map (lambda (idx)
+                      (remove-nth report idx)) (indexes report))))
+
+(define (safe-report-with-toleration? report)
+  (any safe-report? (gen-reports report)))
+
 (define (part2 lines)
   (let ((reports (lines->number-list lines)))
-    0))
+    (apply + (map (lambda (r)
+                    (if (safe-report-with-toleration? r)
+                        1
+                        0)) reports))))
 
 (define (main)
   (let ((lines (file->list "input.txt")))