diff --git a/lib/src/graph.hpp b/lib/src/graph.hpp
new file mode 100644
index 0000000..288501c
--- /dev/null
+++ b/lib/src/graph.hpp
@@ -0,0 +1,133 @@
+#ifndef __GRAPH_H__
+#define __GRAPH_H__
+
+#include <algorithm>
+#include <initializer_list>
+#include <iostream>
+#include <unordered_map>
+#include <vector>
+
+template <typename T, typename NameType>
+class Node {
+ public:
+  Node(NameType name) : name{name}, paths{} {}
+  NameType name{NameType()};
+  std::unordered_map<Node*, T> paths;
+
+  void descr_path(Node* n, T lenght = 1) { paths[n] = lenght; }
+
+  ~Node() {
+    paths = {};
+    name = NameType();
+  }
+};
+
+template <typename T, typename NameType>
+class Graph {
+  static_assert(std::is_arithmetic<T>::value,
+                "Graph: paths' lenghts must be arithmetic!");
+
+ public:
+  Graph(std::initializer_list<std::pair<NameType, NameType>> links,
+        T base_lenght = 1) {
+    add_paths(links, base_lenght);
+  }
+
+  Graph(std::initializer_list<std::pair<std::pair<NameType, NameType>, T>>
+            links) {
+    add_paths(links);
+  }
+
+  Node<T, NameType>* find_via_name(NameType name) {
+    auto ans = std::find_if(
+        nodes.begin(), nodes.end(),
+        [&name](const Node<T, NameType>* x) { return x->name == name; });
+    if (ans == nodes.end()) {
+      return nullptr;
+    }
+    return *ans;
+  }
+
+  Node<T, NameType>* operator[](NameType name) { find_via_name(name); }
+
+  void add_paths(std::initializer_list<std::pair<NameType, NameType>> links,
+                 T base_lenght = 1) {
+    /* { {Name1, Name2}, ... }*/
+    for (auto i : links) {
+      Node<T, NameType>* first = find_via_name(i.first);
+      if (!first) {
+        first = new Node<T, NameType>{i.first};
+        nodes.push_back(first);
+      }
+      Node<T, NameType>* second = find_via_name(i.second);
+      if (!second && first != second) {
+        second = new Node<T, NameType>{i.second};
+        nodes.push_back(second);
+      }
+      first->descr_path(second, base_lenght);
+      continue;
+    }
+  }
+
+  void add_paths(
+      std::initializer_list<std::pair<std::pair<NameType, NameType>, T>>
+          links) {
+    /* { { Name1, Name2 }, lenght }, ... }
+     */
+    for (auto i : links) {
+      Node<T, NameType>* first = find_via_name(i.first.first);
+      if (!first) {
+        first = new Node{i.first.first};
+        nodes.push_back(first);
+      }
+      Node<T, NameType>* second = find_via_name(i.first.second);
+      if (!second && first != second) {
+        second = new Node{i.first.second};
+        nodes.push_back(second);
+      }
+      first->descr_path(second, i.second);
+      continue;
+    }
+  }
+
+  ~Graph() {
+    for (Node<T, NameType>* i : nodes) {
+      delete i;
+    }
+    nodes = {};
+  }
+
+  void see_vertical() {
+    for (auto i : nodes) {
+      if (i->paths.size() == 0) {
+        std::cout << i->name << std::endl;
+        continue;
+      }
+      for (auto k : i->paths) {
+        std::cout << i->name << " -> " << k.first->name << ", l:" << k.second
+                  << std::endl;
+      }
+    }
+  }
+
+  friend std::ostream& operator<<(std::ostream& os,
+                                  const Graph<T, NameType>& g) {
+    os << "Graph( ";
+    for (auto i : g.nodes) {
+      if (i->paths.size() == 0) {
+        os << "{" << i->name << "}";
+        continue;
+      }
+      for (auto k : i->paths) {
+        os << "{" << i->name << " -> " << k.first->name << ", l:" << k.second
+           << "}, ";
+      }
+    }
+    os << ")";
+    return os;
+  }
+
+  std::vector<Node<T, NameType>*> nodes;
+};
+
+#endif
diff --git a/task_01/src/main.cpp b/task_01/src/main.cpp
index 76e8197..c3aeba4 100644
--- a/task_01/src/main.cpp
+++ b/task_01/src/main.cpp
@@ -1 +1 @@
-int main() { return 0; }
+int main() { return 0; }
\ No newline at end of file
diff --git a/task_01/src/test.cpp b/task_01/src/test.cpp
index 87cef73..4f86f1a 100644
--- a/task_01/src/test.cpp
+++ b/task_01/src/test.cpp
@@ -1,5 +1,73 @@
 #include <gtest/gtest.h>
 
-TEST(Test, Simple) {
-  ASSERT_EQ(1, 1);  // Stack []
-}
\ No newline at end of file
+#include <stdexcept>
+
+#include "topological_sort.hpp"
+
+template <typename T>
+bool check_graph_sorted(Graph<T, int>& g) {
+  for (auto i : g.nodes) {
+    for (auto k : i->paths) {
+      if (i->name >= k.first->name) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+TEST(TopologySort, TestSimple1) {
+  Graph<int, int> g({{1, 4}, {4, 2}, {3, 2}, {4, 3}});
+  ASSERT_EQ(check_graph_sorted(topological_sort(g)), true);  // Stack []
+}
+
+TEST(TopologySort, TestSimple2) {
+  Graph<int, int> g({{1, 2}, {3, 2}, {2, 5}, {4, 2}, {4, 6}, {6, 5}});
+  ASSERT_EQ(check_graph_sorted(topological_sort(g)), true);  // Stack []
+}
+
+TEST(TopologySort, TestExtraSourcePoint1) {
+  Graph<int, int> g({{1, 2}, {3, 2}, {2, 5}, {4, 2}, {4, 6}, {6, 5}, {8, 6}});
+  ASSERT_EQ(check_graph_sorted(topological_sort(g)), true);  // Stack []
+}
+
+TEST(TopologySort, TestExtraSourcePoint2) {
+  Graph<int, int> g({{1, 2}, {3, 2}, {8, 5}, {2, 5}, {4, 2}, {4, 6}, {6, 5}});
+  ASSERT_EQ(check_graph_sorted(topological_sort(g)), true);  // Stack []
+}
+
+TEST(TopologySort, TestExtraSourcePoint3) {
+  Graph<int, int> g({{1, 4}, {4, 2}, {3, 2}, {4, 3}, {9, 1}});
+  ASSERT_EQ(check_graph_sorted(topological_sort(g)), true);  // Stack []
+}
+
+TEST(TopologySort, TestExtraSourcePoint4) {
+  Graph<int, int> g({{1, 2}, {3, 2}, {6, 5}, {2, 5}, {4, 2}, {4, 6}, {6, 5}});
+  ASSERT_EQ(check_graph_sorted(topological_sort(g)), true);  // Stack []
+}
+
+TEST(TopologySort, TestExtraLeafPoint) {
+  Graph<int, int> g({{1, 2}, {3, 2}, {6, 9}, {2, 5}, {4, 2}, {4, 6}, {6, 5}});
+  ASSERT_EQ(check_graph_sorted(topological_sort(g)), true);  // Stack []
+}
+
+TEST(TopologySort, TestLoopError1) {
+  Graph<int, int> g({{1, 4}, {4, 2}, {3, 2}, {4, 3}, {3, 3}});
+  EXPECT_THROW(topological_sort(g), std::runtime_error);  // Stack []
+}
+
+TEST(TopologySort, TestLoopError2) {
+  Graph<int, int> g({{1, 2}, {1, 3}, {3, 2}, {2, 3}});
+  EXPECT_THROW(topological_sort(g), std::runtime_error);  // Stack []
+}
+
+TEST(TopologySort, TestLoopError3) {
+  Graph<int, int> g({{1, 4}, {4, 2}, {3, 2}, {4, 3}, {4, 1}});
+  EXPECT_THROW(topological_sort(g),
+               std::runtime_error);  // Stack []
+}
+
+TEST(TopologySort, TestLoopError4) {
+  Graph<int, int> g({{1, 2}, {1, 3}, {3, 2}, {2, 3}, {2, 1}, {3, 1}});
+  EXPECT_THROW(topological_sort(g), std::runtime_error);  // Stack []
+}
diff --git a/task_01/src/topological_sort.hpp b/task_01/src/topological_sort.hpp
new file mode 100644
index 0000000..89698df
--- /dev/null
+++ b/task_01/src/topological_sort.hpp
@@ -0,0 +1,49 @@
+#ifndef __TOPOLOG_SORT_H__
+#define __TOPOLOG_SORT_H__
+
+#include <stdexcept>
+#include <vector>
+
+#include "../../lib/src/graph.hpp"
+
+template <typename T>
+void topological_rec(std::vector<Node<T, int>*>& st, Node<T, int>* n) {
+  if (n->name == 0) {
+    n->name = 1;
+    // 1 - adjacent (as leafs) points
+
+    for (auto i : n->paths) {
+      topological_rec(st, i.first);
+    }
+    n->name = 2;
+    st.push_back(n);
+
+  } else if (n->name == 2) {
+    return;
+  } else {
+    throw std::runtime_error("Incorrect graph");
+  }
+}
+
+template <typename T>
+Graph<T, int>& topological_sort(Graph<T, int>& g) {
+  std::vector<Node<T, int>*> marked_points;
+  for (auto i : g.nodes) {
+    i->name = 0;
+    // 0 - clear points
+  }
+
+  // point_stack.push(g.nodes[0]);
+  for (auto i : g.nodes) {
+    if (i->name == 0) {
+      topological_rec(marked_points, i);
+    }
+  }
+  int stack_size = marked_points.size();
+  for (int i = 1; i < stack_size + 1; ++i) {
+    marked_points[stack_size - i]->name = i;
+  }
+  return g;
+}
+
+#endif
\ No newline at end of file