diff --git a/src/generator/generator.py b/src/generator/generator.py
index 4978067..f7f3e6a 100644
--- a/src/generator/generator.py
+++ b/src/generator/generator.py
@@ -455,14 +455,13 @@ def _remove_duplicate_headings(text: str) -> str:
         line = lines[i].rstrip()
         if line.startswith('# ') and not line.startswith('## '):
             h1_text = line[2:].strip().lower()
-            prev_heading = ''
-            for prev in reversed(result):
-                prev_stripped = prev.strip()
-                if prev_stripped:
-                    if prev_stripped.startswith('## '):
-                        prev_heading = prev_stripped[3:].strip().lower()
-                    break
-            if prev_heading and prev_heading == h1_text:
+            window = result[-5:] if len(result) >= 5 else result[:]
+            recent_h2s = {
+                p.strip()[3:].strip().lower()
+                for p in window
+                if p.strip().startswith('## ')
+            }
+            if h1_text in recent_h2s:
                 i += 1
                 continue
         result.append(lines[i])