upload

3/A.cpp

@@ -0,0 +1,59 @@
+#include <iostream>
+
+struct Node {
+  Node* next;
+  int message;
+};
+
+class Stack {
+ private:
+  Node* first = nullptr;
+
+ public:
+  void Add(int message) {
+    Node* new_node = new Node{first, message};
+    first = new_node;
+  };
+
+  int Poop() {
+    Node* last = first;
+    int return_value = last->message;
+    first = last->next;
+    delete last;
+    return return_value;
+  }
+};
+
+int main() {
+  Stack stack;
+  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;
+
+      stack.Add(message);
+    } else {
+      return_values[stack_idx] = stack.Poop();
+      ++stack_idx;
+    }
+  }
+
+  for (int i = 0; i < stack_idx; ++i) {
+    std::cout << return_values[i] << '\n';
+  }
+
+  delete[] return_values;
+
+  return 0;
+}