Merge pull request #195 from dhiaeddineTounakti/push_heap

added push_heap function

algorithm/push_heap.md

@@ -0,0 +1,36 @@
+# push_heap
+
+**Description** : Given a heap in the range [first,last-1), this function extends the range considered a heap to [first,last) by placing the value in (last-1) into its corresponding location within it. 
+
+**Example**:
+```cpp
+#include <iostream>     // std::cout
+#include <algorithm>    // std::make_heap, std::pop_heap, std::push_heap, std::sort_heap
+#include <vector>       // std::vector
+
+int main () {
+  int myints[] = {10,20,30,5,15};
+  std::vector<int> v(myints,myints+5);
+
+  std::make_heap (v.begin(),v.end());
+  std::cout << "initial max heap   : " << v.front() << '\n';
+
+  std::pop_heap (v.begin(),v.end()); v.pop_back();
+  std::cout << "max heap after pop : " << v.front() << '\n';
+
+  v.push_back(99); std::push_heap (v.begin(),v.end());
+  std::cout << "max heap after push: " << v.front() << '\n';
+
+  std::sort_heap (v.begin(),v.end());
+
+  std::cout << "final sorted range :";
+  for (unsigned i=0; i<v.size(); i++)
+    std::cout << ' ' << v[i];
+
+  std::cout << '\n';
+
+  return 0;
+}
+```
+
+**[Run Code](https://rextester.com/WWHJ67453)**