ccoommmmiitt 33 iinn ccpppp

5/binary_tree.cpp

@@ -1,102 +1,117 @@
 #include <iostream>
 #include <vector>
+#include <cmath>
 
-int log2int(int n){
-    if (n <= 1){
-        return 0; // no support + n is int anyway
-    }
-    return 1 + log2int(n / 2);
-}
 class binary_tree
 {
 public:
     binary_tree() {}
+
     void append(int x)
     {
         data.push_back(x);
-        maintain_shape(0);
+        bubble_up(data.size() - 1);
     }
-    void maintain_shape(int ind)
+
+    void add(std::vector<int> add)
     {
-        int left = 2 * ind + 1;
-        int right = 2 * ind + 2; // damn this is accounted for 0 indexing gj ai
-        if (left > data.size())
-        { // 100% leaf
-            return;
+        for (int x : add)
+        {
+            append(x);
         }
-        if (right > data.size())
-        { // only node is left, and that node is also last ele in data
-            if (data[ind] < data[left])
-            {
-                std::swap(data[ind], data[left]); // bigger higher
-            }
-            return;
-        }
-        maintain_shape(left);
-        maintain_shape(right);
-        // ordering? so the last item at index data.size() - 1 isnt swapped last: may lead to problem??? idk
-        if (data[ind] < data[left])
-            std::swap(data[ind], data[left]);
-        if (data[ind] < data[right])
-            std::swap(data[ind], data[right]);
     }
-    int pop() {
+
+    int pop()
+    {
+        if (data.empty())
+            throw std::runtime_error("Heap is empty");
         int ret = data[0];
-        data[0] = data[data.size() - 1];
+        data[0] = data.back();
         data.pop_back();
-        maintain_shape(0);
+        if (!data.empty())
+            sift_down(0);
         return ret;
     }
-    void add(std::vector<int> add) {
-        for (int i = 0; i < add.size(); i++) {
-            data.push_back(add[i]);
-        }
-        maintain_shape(0);
-    }
-    void print() {
-        // insane sauce:
-        int twos = 0;
 
-        for (int i = 0; i < data.size(); i++) {
-            if (log2int(i + 1) == twos + 1) {
-                std::cout << std::endl;
-                twos++;
-            } 
+    void print()
+    {
+        int levels = 0;
+        for (int i = 0; i < data.size(); i++)
+        {
+            if (log2int(i + 1) == levels + 1)
+            {
+                std::cout << "\n";
+                levels++;
+            }
             std::cout << data[i] << " ";
         }
-        std::cout << std::endl;
+        std::cout << "\n";
     }
+
 private:
     std::vector<int> data;
-};
 
+    int log2int(int n)
+    {
+        int log = 0;
+        while (n > 1)
+        {
+            n /= 2;
+            log++;
+        }
+        return log;
+    }
+
+    void bubble_up(int idx)
+    {
+        while (idx > 0)
+        {
+            int parent = (idx - 1) / 2;
+            if (data[parent] >= data[idx])
+                break;
+            std::swap(data[parent], data[idx]);
+            idx = parent;
+        }
+    }
+
+    void sift_down(int idx)
+    {
+        while (true)
+        {
+            int left = 2 * idx + 1;
+            int right = 2 * idx + 2;
+            int largest = idx;
+
+            if (left < data.size() && data[left] > data[largest])
+                largest = left;
+            if (right < data.size() && data[right] > data[largest])
+                largest = right;
+
+            if (largest == idx)
+                break;
+
+            std::swap(data[idx], data[largest]);
+            idx = largest;
+        }
+    }
+};
 
 int main(int argc, char const *argv[])
 {
     binary_tree bt;
-    bt.append(1);
-    bt.append(2);
-    bt.append(6);
-    std::cout << "\n";
-    bt.print();
-    bt.append(4);
+    bt.append(10);
+    bt.append(20);
     bt.append(5);
-    std::cout << "\n";
-    bt.print();
-    bt.append(9);
-    std::cout << "\n";
-    bt.print();
-    bt.append(8);
-    std::cout << "\n";
+    bt.append(6);
+    bt.append(15);
     bt.print();
+
     int popped = bt.pop();
-    std::cout << "popped: " << popped << std::endl;
+    std::cout << "Popped: " << popped << "\n";
     bt.print();
-    popped = bt.pop();
-    std::cout << "popped: " << popped << std::endl;
-    bt.print();
-    bt.add({6,5,11, 8, 10,15,3,7,1,12,4, 9});
-    std::cout << "\n";
+
+    bt.add({50, 40, 60});
     bt.print();
+
     return 0;
 }