diff --git a/modules/08_stl_algorithms/src/sort_and_find.cpp b/modules/08_stl_algorithms/src/sort_and_find.cpp
index 19a7384..fe17fd6 100644
--- a/modules/08_stl_algorithms/src/sort_and_find.cpp
+++ b/modules/08_stl_algorithms/src/sort_and_find.cpp
@@ -1,9 +1,19 @@
 #include "sort_and_find.hpp"
 
+#include <algorithm>
+
 namespace stl_algorithms {
 
-auto sorted_copy(std::vector<int> data) -> std::vector<int> { (void)data; return {}; }
-auto contains(const std::vector<int>& data, int value) -> bool { (void)data; (void)value; return false; }
-auto lower_bound_index(const std::vector<int>& sorted, int value) -> int { (void)sorted; (void)value; return -1; }
+auto sorted_copy(std::vector<int> data) -> std::vector<int> {
+    std::ranges::sort(data);
+    return data;
+}
+auto contains(const std::vector<int>& data, const int value) -> bool {
+    return std::ranges::find(data, value) != data.end();
+}
+    
+auto lower_bound_index(const std::vector<int>& sorted, const int value) -> int {
+    return static_cast<int>(std::ranges::lower_bound(sorted, value) - sorted.begin());
+}
 
 }  // namespace stl_algorithms