From 80c709b673c73ca150e5508343fcde6b2be2695c Mon Sep 17 00:00:00 2001
From: NaiJi <naijiworld@protonmail.com>
Date: Mon, 20 Sep 2021 15:37:15 +0300
Subject: [PATCH] 6.1

---
 6.1/graph.cpp | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)
 create mode 100644 6.1/graph.cpp

diff --git a/6.1/graph.cpp b/6.1/graph.cpp
new file mode 100644
index 0000000..c946faf
--- /dev/null
+++ b/6.1/graph.cpp
@@ -0,0 +1,94 @@
+#include <iostream>
+#include <memory>
+#include <limits>
+
+template <typename T>
+struct ListNode
+{
+    T value;
+    std::shared_ptr<ListNode<T>> next;
+};
+
+template <typename T>
+struct List
+{
+    std::shared_ptr<ListNode<T>> head;
+};
+
+template <typename T>
+struct GraphNode
+{
+    T value;
+    List<std::shared_ptr<GraphNode<T>>> relations;
+};
+
+using T = char;
+using GraphNodeT = std::shared_ptr<GraphNode<T>>;
+using ListNodeT = ListNode<std::shared_ptr<GraphNode<T>>>;
+
+bool step(const GraphNodeT& node, std::size_t counter, std::size_t& min, const GraphNodeT& goal)
+{
+    if (!node)
+        return false;
+
+    std::cout << "Step: " << node->value << ";\n";
+
+    if (node == goal)
+    {
+        min = counter;
+        return true;
+    }
+
+    bool found = false;
+
+    if (counter < min)
+    {
+        auto iter_node = node->relations.head;
+        while (iter_node)
+        {
+            found = found || step(iter_node->value, counter + 1, min, goal);
+            iter_node = iter_node->next;
+        }
+    }
+
+    return found;
+}
+
+std::size_t findPath(const GraphNodeT& root, const GraphNodeT& goal)
+{
+    if (!root || !goal)
+        return 0;
+
+    std::size_t min = std::numeric_limits<std::size_t>::max();
+
+    return step(root, 0, min, goal)
+         ? min
+         : 0;
+}
+
+int main()
+{
+    auto s  = std::make_shared<GraphNode<T>>(GraphNode<T>{'s', {}});
+    auto e1 = std::make_shared<GraphNode<T>>(GraphNode<T>{'1', {}});
+    auto e2 = std::make_shared<GraphNode<T>>(GraphNode<T>{'2', {}});
+    auto e3 = std::make_shared<GraphNode<T>>(GraphNode<T>{'3', {}});
+    auto e4 = std::make_shared<GraphNode<T>>(GraphNode<T>{'4', {}});
+    auto f  = std::make_shared<GraphNode<T>>(GraphNode<T>{'f', {}});
+
+    s->relations.head = std::make_shared<ListNodeT>();
+    s->relations.head->value = e1;
+    s->relations.head->next = std::make_shared<ListNodeT>();
+    s->relations.head->next->value = e2;
+    e1->relations.head = std::make_shared<ListNodeT>();
+    e1->relations.head->value = f;
+    e1->relations.head->next = std::make_shared<ListNodeT>();
+    e1->relations.head->next->value = e3;
+    e2->relations.head = std::make_shared<ListNodeT>();
+    e2->relations.head->value = e3;
+    e2->relations.head->next = std::make_shared<ListNodeT>();
+    e2->relations.head->next->value = e4;
+    e4->relations.head = std::make_shared<ListNodeT>();
+    e4->relations.head->value = f;
+
+    std::cout << "Min: " << findPath(s, f) << "\n\n\n\n";
+}