add TODO

lib/kyut/Reordering-inl.hpp

@@ -25,6 +25,8 @@ namespace kyut {
             // Sort the chunk.
             std::sort(begin, end, less);
 
+            // TODO: Assume unique
+
             // Embed watermark.
             const std::size_t count = std::distance(begin, end);
             const std::size_t bit_width = factorial_bit_width_table[count];
@@ -87,6 +89,8 @@ namespace kyut {
                 return less(*a, *b);
             });
 
+            // TODO: Assume unique
+
             const auto chunk_begin = std::begin(chunk);
             const auto chunk_end = std::end(chunk);