delete pics to save space

2.11995.cpp

@@ -0,0 +1,72 @@
+#include<cstdio>
+#include<queue>
+#include<stack>
+using namespace std;
+int n,s,q,h;
+int a[1005],x[1005];
+bool is_stk()
+{
+	stack<int> stk;
+	for(int i=0;i<n;i++)
+	{
+		if(a[i]==1) stk.push(x[i]);
+		else
+		{
+			if(stk.empty()) return false;
+			if(x[i]!=stk.top()) return false;
+			stk.pop();
+		}
+	}
+	return true;
+}
+bool is_que()
+{
+	queue<int> que;
+	for(int i=0;i<n;i++)
+	{
+		if(a[i]==1) que.push(x[i]);
+		else
+		{
+			if(que.empty()) return false;
+			if(x[i]!=que.front()) return false;
+			que.pop();
+		}
+	}
+	return true;
+}
+bool is_heap()
+{
+	priority_queue<int> heap;
+	for(int i=0;i<n;i++)
+	{
+		if(a[i]==1) heap.push(x[i]);
+		else
+		{
+			if(heap.empty()) return false;
+			if(x[i]!=heap.top()) return false;
+			heap.pop();
+		}
+	}
+	return true;
+}
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	while(scanf("%d",&n)==1)
+	{
+		stack<int> stk;
+		queue<int> que;
+		priority_queue<int> heap;
+		for(int i=0;i<n;i++)
+			scanf("%d%d",a+i,x+i);
+		s=is_stk();q=is_que();h=is_heap();
+		if(s+q+h>=2) printf("not sure\n");
+		else if(s) printf("stack\n");
+		else if(q) printf("queue\n");
+		else if(h) printf("priority queue\n");
+		else printf("impossible\n");
+	}
+	return 0;
+}