B3614 【模板】栈

https://www.luogu.com.cn/record/130382070

Luogu/B3614/B3614.cpp

@@ -0,0 +1,52 @@
+#include <iostream>
+#include <stack>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    int t;
+
+    cin >> t;
+
+    while (t--) {
+        int n;
+        std::stack<unsigned long long> st;
+
+        cin >> n;
+
+        while (n--) {
+            std::string op;
+
+            cin >> op;
+
+            if (op == "push") {
+                unsigned long long x;
+
+                cin >> x;
+
+                st.emplace(x);
+            } else if (op == "pop") {
+                if (st.empty()) {
+                    cout << "Empty" << endl;
+                } else {
+                    st.pop();
+                }
+            } else if (op == "query") {
+                if (st.empty()) {
+                    cout << "Anguei!" << endl;
+                } else {
+                    cout << st.top() << endl;
+                }
+            } else if (op == "size") {
+                cout << st.size() << endl;
+            }
+        }
+    }
+
+    return 0;
+}