1 files changed, 77 insertions, 0 deletions
diff --git a/Year_1/Programming_2/exercises/doppioni.cc b/Year_1/Programming_2/exercises/doppioni.cc
new file mode 100644
index 0000000..fdd3e88
--- /dev/null
+++ b/Year_1/Programming_2/exercises/doppioni.cc
@@ -0,0 +1,77 @@
+#include<iostream>
+#include<fstream>
+
+using namespace std;
+
+template<class T>
+class node {
+public:
+    node(T key, node* parent, node* right, node* left) : _key{key}, _parent{parent}, _right{right}, _left{left} {}
+    T& key() { return _key; }
+    const T& key() const { return _key; }
+    node<T>*& parent() { return _parent; }
+    const node<T>*& parent() const { return _parent; }
+    node<T>*& right() { return _right; }
+    const node<T>*& right() const { return _right; }
+    node<T>*& left() { return _left; }
+    const node<T>*& left() const { return _left; }
+private:
+    T _key;
+    node<T>* _parent;
+    node<T>* _right;
+    node<T>* _left;
+};
+
+class bst {
+public:
+    bst() : _duplicates{0}, _root{nullptr} {}
+    bst* add(int val) {
+        node<int>* iter = _root;
+        node<int>* prev = nullptr;
+        while(iter) {
+            prev = iter;
+            if(iter->key() == val) {
+                _duplicates++;
+                return this;
+            }
+
+            if(iter->key() > val)
+                iter = iter->right();
+            else
+                iter = iter->left();
+        }
+
+        node<int>* nodus = new node<int>{val, prev, nullptr, nullptr};
+        if(!prev)
+            _root = nodus;
+        else if(prev->key() > val)
+            prev->right() = nodus;
+        else
+            prev->left() = nodus;
+
+        return this;
+    }
+    const int& duplicates() const { return _duplicates; }
+private:
+    int _duplicates;
+    node<int>* _root;
+};
+
+int main() {
+    ifstream in("input.txt");
+    ofstream out("output.txt");
+    for(int ts = 0; ts < 100; ++ts) {
+        bst* b = new bst{};
+        int n;
+        in >> n;
+        int e;
+        for(int i = 0; i < n; ++i) {
+            in >> e;
+            b->add(e);
+        }
+        out << b->duplicates() << endl;
+    }
+    in.close();
+    out.close();
+    return 0;
+}