support bazel complie this project and format code.

learn_class/modern_cpp_30/container2/priority_queue.cpp

@@ -0,0 +1,26 @@
+//
+// Created by light on 19-12-16.
+//
+
+#include "../container1/output_container.h"
+#include <functional> // std::greater
+#include <iostream>   // std::cout/endl
+#include <memory>     // std::pair
+#include <queue>      // std::priority_queue
+#include <vector>     // std::vector
+
+using namespace std;
+
+int main() {
+  priority_queue<pair<int, int>, vector<pair<int, int>>,
+                 greater<pair<int, int>>>
+      q;
+  q.push({1, 1});
+  q.push({2, 2});
+  q.push({0, 3});
+  q.push({9, 4});
+  while (!q.empty()) {
+    cout << q.top() << endl;
+    q.pop();
+  }
+}