upload

3/B.cpp

@@ -0,0 +1,70 @@
+#include <iostream>
+
+struct Node {
+  Node* next;
+  int message;
+};
+
+class Queue {
+ private:
+  Node* first = nullptr;
+  Node* last = nullptr;
+  size_t size = 0;
+ public:
+  void Add(int message) {
+    Node* new_node = new Node {nullptr, message};
+    if (size == 0) {
+      first = new_node;
+    } else {
+      last->next = new_node;
+    }
+    ++size;
+    last = new_node;
+  }
+
+  int Pop() {
+    if (size != 0) {
+      Node* prev = first;
+      int return_value = prev->message;
+      first = prev->next;
+      delete prev;
+      --size;
+      return return_value;
+    }
+  }
+
+};
+
+int main() {
+  Queue queue;
+  int n;
+  int stack_idx = 0;
+
+  std::cin >> n;
+
+  int* return_values = new int[n];
+
+  for (int i = 0; i < n; ++i) {
+    char action;
+    std::cin >> action;
+
+    if (action == '+') {
+      int message;
+
+      std::cin >> message;
+
+      queue.Add(message);
+    } else {
+      return_values[stack_idx] = queue.Pop();
+      ++stack_idx;
+    }
+  }
+
+  for (int i = 0; i < stack_idx; ++i) {
+    std::cout << return_values[i] << '\n';
+  }
+
+  delete[] return_values;
+
+  return 0;
+}