added

3 files changed, 20 insertions, 6 deletions

diff --git a/debug.h b/debug.h
index 7d739ae..407ef25 100644
--- a/debug.h
+++ b/debug.h
@@ -50,9 +50,9 @@ template <typename T> ostream &operator<<(ostream &out, const Binary<T> &b) {
   return out << ")_2";
 }
 
-template <ranges::forward_range RangeT>
-ostream &operator<<(ostream &out, RangeT &&range)
-  requires(!same_as<ranges::range_value_t<RangeT>, char>)
+template <ranges::forward_range Range>
+ostream &operator<<(ostream &out, Range &&range)
+  requires(!same_as<ranges::range_value_t<Range>, char>)
 {
   out << "[";
   bool first = true;
diff --git a/fixed_size_upper_matrix.h b/fixed_size_upper_matrix.h
index 307d648..5df624b 100644
--- a/fixed_size_upper_matrix.h
+++ b/fixed_size_upper_matrix.h
@@ -1,10 +1,8 @@
 #pragma once
 
 #include <array>
-#include <cstdint>
 #include <cstring>
 #include <initializer_list>
-#include <vector>
 
 template <typename T, int N>
 struct FixedSizeUpperMatrixT : std::array<std::array<T, N>, N> {
@@ -58,7 +56,7 @@ struct FixedSizeUpperMatrixT : std::array<std::array<T, N>, N> {
         buffer[i] = o[i][j];
       }
       for (int i = 0; i <= j; ++i) {
-        for (int k = i; k < N; ++k) {
+        for (int k = i; k <= j; ++k) {
           result[i][j] += (*this)[i][k] * buffer[k];
         }
       }
diff --git a/snippets/group.h b/snippets/group.h
new file mode 100644
index 0000000..bd183e0
--- /dev/null
+++ b/snippets/group.h
@@ -0,0 +1,16 @@
+#pragma once
+
+#include <functional>
+#include <ranges>
+
+template <std::ranges::random_access_range Range>
+void group(const Range &v, const std::function<void(int, int)> &fn) {
+  int n = v.size();
+  for (int i = 0; i < n;) {
+    auto i0 = i;
+    while (i < n && v[i0] == v[i]) {
+      i++;
+    }
+    fn(i0, i);
+  }
+}