diff --git a/binary_search_tree.h b/binary_search_tree.h
index 2179f72..400d48f 100644
--- a/binary_search_tree.h
+++ b/binary_search_tree.h
@@ -1,5 +1,6 @@
 #ifndef _UTIL_BINARY_SEARCH_TREE_H
 #define _UTIL_BINARY_SEARCH_TREE_H
+#include <exception>
 #include "binary_tree.h"
 
 template <typename K, typename V>
@@ -28,6 +29,116 @@ inline void binary_search_tree_clear(BinarySearchTree<K, V>*& root, F free_key,
     binary_search_tree_clear(root, std::function<void(K)>(free_key), std::function<void(V)>(free_value));
 }
 
+template <typename K, typename V>
+bool binary_search_tree_delete(BinarySearchTree<K, V>*& root, K key, V* deleted_value, std::function<int(K, K)> comp, std::function<void(K)> free_key = std::function<void(K)>(), std::function<void(V)> free_value = std::function<void(V)>()) {
+    if (!root) return false;
+    BinarySearchTree<K, V>* cur = root, *prev = nullptr;
+    while (cur) {
+        int re = comp(key, cur->data.key);
+        if (re == 0) {
+            break;
+        }
+        prev = cur;
+        cur = re < 0 ? cur->left : cur->right;
+    }
+    if (!cur) return false;
+    if (binary_tree_is_leaf(cur)) {
+        if (prev) prev->left == cur ? prev->left = nullptr : prev->right = nullptr;
+        else root = nullptr;
+    } else if (!cur->right) {
+        if (prev) prev->left == cur ? prev->left = cur->left : prev->right = cur->left;
+        else root = cur->left;
+    } else if (!cur->left) {
+        if (prev) prev->left == cur ? prev->left = cur->right : prev->right = cur->right;
+        else root = cur->right;
+    } else {
+        prev = cur;
+        BinarySearchTree<K, V>* tmp = cur->left;
+        while (tmp->right) {
+            prev = tmp;
+            tmp = tmp->right;
+        }
+        K tk = tmp->data.key;
+        V tv = tmp->data.value;
+        tmp->data.key = cur->data.key;
+        tmp->data.value = cur->data.value;
+        cur->data.key = tk;
+        cur->data.value = tv;
+        cur = tmp;
+        prev->left == cur ? prev->left = nullptr : prev->right = nullptr;
+    }
+    if (free_key) free_key(cur->data.key);
+    if (deleted_value) *deleted_value = cur->data.value;
+    if (!deleted_value && free_value) free_value(cur->data.value);
+    free(cur);
+    return true;
+}
+
+template <typename K, typename V, class F, class G, class H>
+inline bool binary_search_tree_delete(BinarySearchTree<K, V>*& root, K key, V* deleted_value, F comp, G free_key, H free_value) {
+    return binary_search_tree_delete(root, key, deleted_value, std::function<int(K, K)>(comp), std::function<void(K)>(free_key), std::function<void(V)>(free_value));
+}
+
+template <typename K, typename V>
+bool binary_search_tree_delete(BinarySearchTree<K, V>*& root, K key, V* deleted_value = nullptr) {
+    return binary_search_tree_delete(root, key, deleted_value, [](K k1, K k2) {
+        return k1 == k2 ? 0 : k1 < k2 ? -1 : 1;
+    }, nullptr, nullptr);
+}
+
+template <typename K, typename V>
+bool binary_search_tree_get(BinarySearchTree<K, V>* root, K key, V& value, std::function<int(K, K)> comp) {
+    if (!root) return false;
+    BinarySearchTree<K, V>* cur = root;
+    while (cur) {
+        int re = comp(key, cur->data.key);
+        if (re == 0) {
+            value = cur->data.value;
+            return true;
+        }
+        cur = re < 0 ? cur->left : cur->right;
+    }
+    return false;
+}
+
+template <typename K, typename V, class F>
+inline bool binary_search_tree_get(BinarySearchTree<K, V>* root, K key, V& value, F comp) {
+    return binary_search_tree_get(root, key, value, std::function<int(K, K)>(comp));
+}
+
+template <typename K, typename V>
+bool binary_search_tree_get(BinarySearchTree<K, V>* root, K key, V& value) {
+    return binary_search_tree_get(root, key, value, [](K k1, K k2) {
+        return k1 == k2 ? 0 : k1 < k2 ? -1 : 1;
+    });
+}
+
+template <typename K, typename V>
+BinarySearchTree<K, V>* binary_search_tree_get_node(BinarySearchTree<K, V>* root, K key, std::function<int(K, K)> comp) {
+    if (!root) return nullptr;
+    BinarySearchTree<K, V>* cur = root;
+    while (cur) {
+        int re = comp(key, cur->data.key);
+        if (re == 0) {
+            return cur;
+        }
+        cur = re < 0 ? cur->left : cur->right;
+    }
+    return nullptr;
+}
+
+template <typename K, typename V, class F>
+inline BinarySearchTree<K, V>* binary_search_tree_get_node(BinarySearchTree<K, V>* root, K key, F comp) {
+    return binary_search_tree_get_node(root, key, std::function<int(K, K)>(comp));
+}
+
+template <typename K, typename V>
+BinarySearchTree<K, V>* binary_search_tree_get_node(BinarySearchTree<K, V>* root, K key) {
+    return binary_search_tree_get_node(root, key, [](K k1, K k2) {
+        return k1 == k2 ? 0 : k1 < k2 ? -1 : 1;
+    });
+}
+
 template <typename K, typename V, typename... Args>
 void binary_search_tree_iter(BinarySearchTree<K, V>* root, std::function<void(K, V, Args...)> callback, Args... args) {
     binary_tree_lnr(root, [&callback](BinarySearchTree<K, V>* e, Args... args) {
@@ -41,14 +152,14 @@ inline void binary_search_tree_iter(BinarySearchTree<K, V>* root, F callback, Ar
 }
 
 template <typename K, typename V>
-bool binary_search_tree_insert(BinarySearchTree<K, V>*& root, K key, V value, std::function<int(K, K)> comp, std::function<void(K)> free_key = std::function<void(K)>(), std::function<void(V)> free_value = std::function<void(V)>()) {
+BinarySearchTree<K, V>* binary_search_tree_insert(BinarySearchTree<K, V>*& root, K key, V value, std::function<int(K, K)> comp, std::function<void(K)> free_key = std::function<void(K)>(), std::function<void(V)> free_value = std::function<void(V)>()) {
     if (!root) {
         root = binary_tree_new<BinarySearchTreePair<K, V>>({ key, value });
         if (!root) {
             if (free_key) free_key(key);
             if (free_value) free_value(value);
         }
-        return root != nullptr;
+        return root;
     }
     BinarySearchTree<K, V>* cur = root;
     int re = comp(key, cur->data.key);
@@ -65,32 +176,86 @@ bool binary_search_tree_insert(BinarySearchTree<K, V>*& root, K key, V value, st
         if (free_value) free_value(cur->data.value);
         if (free_key) free_key(key);
         cur->data.value = value;
-        return true;
+        return cur;
     }
     BinarySearchTree<K, V>* node = binary_tree_new<BinarySearchTreePair<K, V>>({key, value});
     if (!node) {
         if (free_key) free_key(key);
         if (free_value) free_value(value);
-        return false;
+        return nullptr;
     }
     if (re == -1) {
         cur->left = node;
     } else {
         cur->right = node;
     }
-    return true;
+    return node;
 }
 
 template <typename K, typename V, class F>
-inline bool binary_search_tree_insert(BinarySearchTree<K, V>*& root, K key, V value, F comp) {
+inline BinarySearchTree<K, V>* binary_search_tree_insert(BinarySearchTree<K, V>*& root, K key, V value, F comp) {
     return binary_search_tree_insert(root, key, value, std::function<int(K, K)>(comp));
 }
 
 template <typename K, typename V>
-bool binary_search_tree_insert(BinarySearchTree<K, V>*& root, K key, V value) {
+BinarySearchTree<K, V>* binary_search_tree_insert(BinarySearchTree<K, V>*& root, K key, V value) {
     return binary_search_tree_insert(root, key, value, [](K k1, K k2) {
         return k1 == k2 ? 0 : k1 < k2 ? -1 : 1;
     });
 }
 
+template <typename K, typename V, class Compare = std::less<K>>
+class BinarySearchMap {
+private:
+    BinarySearchTree<K, V>* tree = nullptr;
+    std::function<int(K, V)> comp_func;
+    std::function<void(K)> free_key_func;
+    std::function<void(V)> free_value_func;
+public:
+    BinarySearchMap(std::function<void(K)> free_key = std::function<void(K)>(), std::function<void(V)> free_value = std::function<void(V)>(), Compare cmp = Compare()) {
+        comp_func = std::function([&cmp] (K k1, K k2) {
+            return cmp(k1, k2) ? -1 : cmp(k2, k1) ? 1 : 0;
+        });
+        free_key_func = free_key;
+        free_value_func = free_value;
+    }
+    template <class F, class G>
+    BinarySearchMap(F free_key, G free_value = std::function<void(V)>(), Compare cmp = Compare()) : BinarySearchMap(std::function<void(K)>(free_key), std::function<void(V)>(free_value), cmp) {}
+    ~BinarySearchMap() {
+        clear();
+    }
+    void inline clear() {
+        binary_search_tree_clear(tree, free_key_func, free_value_func);
+    }
+    bool inline del(K key, V* deleted_value = nullptr) {
+        return binary_search_tree_delete(tree, key, deleted_value, comp_func, free_key_func, free_value_func);
+    }
+    bool inline get(K key, V& value) {
+        return binary_search_tree_get(tree, key, value, comp_func);
+    }
+    bool inline insert(K key, V value) {
+        return binary_search_tree_insert(tree, key, value, comp_func, free_key_func, free_value_func) != nullptr;
+    }
+    template <typename ...Args>
+    void inline iter(std::function<void(K, V, Args...)> callback, Args... args) {
+        return binary_search_tree_iter(tree, callback, args...);
+    }
+    template <class F, typename ...Args>
+    void inline iter(F callback, Args... args) {
+        return binary_search_tree_iter(tree, std::function<void(K, V, Args...)>(callback), args...);
+    }
+    V& operator[](K key) {
+        BinarySearchTree<K, V>* node = binary_search_tree_get_node(tree, key, comp_func);
+        if (!node) {
+            V tmp;
+            BinarySearchTree<K, V>* node = binary_search_tree_insert(tree, key, tmp, comp_func, free_key_func, free_value_func);
+            if (!node) {
+                throw std::runtime_error("Failed to insert new node");
+            }
+            return node->data.value;
+        }
+        return node->data.value;
+    }
+};
+
 #endif
diff --git a/test/binary_tree_test.cpp b/test/binary_tree_test.cpp
index 71295a8..46f0efc 100644
--- a/test/binary_tree_test.cpp
+++ b/test/binary_tree_test.cpp
@@ -68,5 +68,96 @@ TEST(BinaryTreeTest, BinarySearchTree1) {
     });
     GTEST_ASSERT_EQ(keys, "20,33,40,77,100,120");
     GTEST_ASSERT_EQ(values, "45,23,13,33,20,222");
+    int v;
+    GTEST_ASSERT_EQ(binary_search_tree_get(tree, 100, v), true);
+    GTEST_ASSERT_EQ(v, 20);
+    GTEST_ASSERT_EQ(binary_search_tree_get(tree, 33, v), true);
+    GTEST_ASSERT_EQ(v, 23);
+    GTEST_ASSERT_EQ(binary_search_tree_get(tree, 119, v), false);
+    GTEST_ASSERT_EQ(v, 23);
+    GTEST_ASSERT_EQ(binary_search_tree_delete(tree, 77, &v), true);
+    GTEST_ASSERT_EQ(v, 33);
+    binary_search_tree_insert(tree, 27, 311);
+    keys = "";
+    values = "";
+    binary_search_tree_iter(tree, [&keys, &values](int key, int value) {
+        if (!keys.empty()) {
+            keys += ",";
+            values += ",";
+        }
+        keys += std::to_string(key);
+        values += std::to_string(value);
+    });
+    GTEST_ASSERT_EQ(keys, "20,27,33,40,100,120");
+    GTEST_ASSERT_EQ(values, "45,311,23,13,20,222");
+    binary_search_tree_insert(tree, 80, 122);
+    GTEST_ASSERT_EQ(binary_search_tree_delete(tree, 33, &v), true);
+    GTEST_ASSERT_EQ(v, 23);
+    GTEST_ASSERT_EQ(binary_search_tree_delete(tree, 40, &v), true);
+    GTEST_ASSERT_EQ(v, 13);
+    keys = "";
+    values = "";
+    binary_search_tree_iter(tree, [&keys, &values](int key, int value) {
+        if (!keys.empty()) {
+            keys += ",";
+            values += ",";
+        }
+        keys += std::to_string(key);
+        values += std::to_string(value);
+    });
+    GTEST_ASSERT_EQ(keys, "20,27,80,100,120");
+    GTEST_ASSERT_EQ(values, "45,311,122,20,222");
+    GTEST_ASSERT_EQ(binary_search_tree_delete(tree, 120), true);
+    GTEST_ASSERT_EQ(binary_search_tree_delete(tree, 120, &v), false);
+    GTEST_ASSERT_EQ(v, 13);
+    auto j = binary_search_tree_get_node(tree, 20);
+    GTEST_ASSERT_EQ(j->data.key, 20);
     binary_search_tree_clear(tree);
 }
+
+TEST(BinaryTreeTest, BinarySearchTree2) {
+    BinarySearchTree<int, int>* tree = nullptr;
+    binary_search_tree_insert(tree, 100, 3);
+    int v;
+    GTEST_ASSERT_EQ(binary_search_tree_delete(tree, 100, &v), true);
+    GTEST_ASSERT_EQ(v, 3);
+    GTEST_ASSERT_EQ(tree, nullptr);
+    binary_search_tree_insert(tree, 2, 3);
+    binary_search_tree_insert(tree, 1, 2);
+    binary_search_tree_insert(tree, 3, 4);
+    GTEST_ASSERT_EQ(binary_search_tree_delete(tree, 2, &v), true);
+    GTEST_ASSERT_EQ(v, 3);
+    GTEST_ASSERT_EQ(tree->data.key, 1);
+    GTEST_ASSERT_EQ(tree->data.value, 2);
+    binary_search_tree_insert(tree, -100, 123);
+    binary_search_tree_insert(tree, -200, 200);
+    binary_search_tree_clear(tree);
+}
+
+TEST(BinaryTreeTest, BinarySearchTree3) {
+    BinarySearchMap<int, int> map;
+    map.insert(20, 30);
+    map.insert(30, 40);
+    map.insert(10, 20);
+    map[20] = 55;
+    map[33] = 44;
+    GTEST_ASSERT_EQ(map[20], 55);
+    GTEST_ASSERT_EQ(map[33], 44);
+    int v;
+    GTEST_ASSERT_EQ(map.get(33, v), true);
+    GTEST_ASSERT_EQ(v, 44);
+    GTEST_ASSERT_EQ(map.del(20, &v), true);
+    GTEST_ASSERT_EQ(v, 55);
+    std::string keys;
+    std::string values;
+    map.iter([&keys, &values](int key, int value) {
+        if (!keys.empty()) {
+            keys += ",";
+            values += ",";
+        }
+        keys += std::to_string(key);
+        values += std::to_string(value);
+    });
+    GTEST_ASSERT_EQ(keys, "10,30,33");
+    GTEST_ASSERT_EQ(values, "20,40,44");
+}