栈的基本操作

Stack.cpp

@@ -0,0 +1,73 @@
+#include <cstdio>
+#include <cstring>
+
+#define ELEMENT_COUNT 100000
+
+using namespace std;
+
+// Requirement: every element in stack must be positive.
+// Otherwise, M[0] should be set to -INF.
+int S[ELEMENT_COUNT], M[ELEMENT_COUNT];
+int sp = 1;
+
+void push(int x)
+{
+	S[sp] = x;
+	if (x > M[sp - 1])
+	{
+		M[sp] = x;
+	}
+	else
+	{
+		M[sp] = M[sp - 1];
+	}
+	sp++;
+}
+
+int pop()
+{
+	return S[--sp];
+}
+
+bool empty()
+{
+	return sp == 1;
+}
+
+int get_max()
+{
+	return M[sp - 1];
+}
+
+int main()
+{
+	while (true)
+	{
+		char o[10];
+		int a;
+		scanf(" %s", o);
+		if (strcmp(o, "push") == 0)
+		{
+			scanf("%d", &a);
+			push(a);
+		}
+		else if (strcmp(o, "pop") == 0)
+		{
+			printf("%d\n", pop());
+		}
+		else if (strcmp(o, "getmax") == 0)
+		{
+			printf("%d\n", get_max());
+		}
+		else if (strcmp(o, "abort") == 0)
+		{
+			return 0;
+		}
+		else
+		{
+			printf("No such instruction.\n");
+		}
+	}
+
+	return 0;
+}