From 62e76e42a08dc6f2ff7b2b77c9108ae83c8cb385 Mon Sep 17 00:00:00 2001
From: Spiros Maggioros <spirosastro@gmail.com>
Date: Sat, 3 Feb 2024 06:03:51 +0200
Subject: [PATCH] added iterators to interval tree class

---
 src/classes/tree/interval_tree.h | 93 ++++++++++++++++++++++++++++++++
 tests/tree/interval_tree.cc      | 10 ++++
 2 files changed, 103 insertions(+)

diff --git a/src/classes/tree/interval_tree.h b/src/classes/tree/interval_tree.h
index 78c6b84e..67149509 100644
--- a/src/classes/tree/interval_tree.h
+++ b/src/classes/tree/interval_tree.h
@@ -69,6 +69,28 @@ template <typename T> class interval_tree {
     return i1.high >= i2.low && i1.low <= i2.high;
   }
 
+  class Iterator;
+
+  /**
+   * @brief pointer that points to begin
+   *
+   * @return Iterator
+   */
+  Iterator begin() {
+    std::vector<std::pair<T, T>> ino = this->inorder();
+    return Iterator(0, ino);
+  }
+
+  /**
+   * @brief pointer that points to end
+   *
+   * @return Iterator
+   */
+  Iterator end() {
+    std::vector<std::pair<T, T>> ino = this->inorder();
+    return Iterator(ino.size(), ino);
+  }
+
   /**
    *@brief inorder function.
    *@returns vector<pair<T,T>>, the elements inorder.
@@ -338,4 +360,75 @@ template <typename T> class interval_tree {
   }
 };
 
+/**
+ * @brief Iterator class
+ */
+template <typename T> class interval_tree<T>::Iterator {
+private:
+  std::vector<std::pair<T, T>> elements;
+  int64_t index;
+
+public:
+  /**
+   * @brief Construct a new Iterator object
+   *
+   * @param els vector<T> - the elements in inorder fashion
+   */
+  explicit Iterator(const int64_t &index,
+                    std::vector<std::pair<T, T>> &els) noexcept
+      : index(index), elements(els) {}
+
+  /**
+   * @brief = operator for Iterator type
+   *
+   * @param index the current index
+   * @return Iterator&
+   */
+  Iterator &operator=(int64_t index) {
+    this->index = index;
+    return *(this);
+  }
+
+  /**
+   * @brief operator ++ for type Iterator
+   *
+   * @return Iterator&
+   */
+  Iterator &operator++() {
+    if (this->index < elements.size()) {
+      this->index++;
+    }
+    return *(this);
+  }
+
+  /**
+   * @brief operator ++ for type Iterator
+   *
+   * @return Iterator
+   */
+  Iterator operator++(int) {
+    Iterator it = *this;
+    ++*(this);
+    return it;
+  }
+
+  /**
+   * @brief operator != for type Iterator
+   *
+   * @param it const Iterator
+   * @return true if index == it.index
+   * @return false otherwise
+   */
+  bool operator!=(const Iterator &it) { return index != it.index; }
+
+  /**
+   * @brief operator * for type Iterator
+   *
+   * @return T the value of the node
+   */
+  std::pair<T, T> operator*() {
+    return {elements[index].first, elements[index].second};
+  }
+};
+
 #endif
diff --git a/tests/tree/interval_tree.cc b/tests/tree/interval_tree.cc
index 0bc074b0..0de28123 100644
--- a/tests/tree/interval_tree.cc
+++ b/tests/tree/interval_tree.cc
@@ -35,4 +35,14 @@ TEST_CASE("testing remove") {
   REQUIRE(i.search({'w', 'w'}) == false);
   REQUIRE(i.search({'c', 'd'}));
   REQUIRE(i.search({'a', 'd'}) == true);
+}
+
+TEST_CASE("testing iterators") {
+  interval_tree<int> i({{1, 3}, {5, 6}, {2, 4}, {9, 10}});
+  std::vector<std::pair<int, int>> els = i.inorder();
+  std::vector<std::pair<int, int>> check;
+  for (auto it = i.begin(); it != i.end(); it++) {
+    check.push_back(*(it));
+  }
+  REQUIRE(check == els);
 }
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