uva 11995 I Can Guess the Data Structure!

题目：I Can Guess the Data Structure!

思路：模拟。

代码：

#include<cstdio>#include<stack>#include<algorithm>#include<queue>#include<deque>using namespace std;int n;int main() {while(~scanf("%d",&n)) {bool fstack=1,fque=1,fpri=1;stack<int> a;queue<int> b;priority_queue<int> c;for(int i=1; i<=n; i++) {int x,y;scanf("%d%d",&x,&y);if(x==1) {a.push(y);b.push(y);c.push(y);}if(x==2) {if(fstack==0||a.empty()||a.top()!=y) fstack=0;else a.pop();if(fque==0||b.empty()||b.front()!=y) fque=0;else b.pop();if(fpri==0||c.empty()||c.top()!=y) fpri=0;else c.pop();}}if(fstack==0&&fque==0&&fpri==0) printf("impossible");else if(fstack==1&&fque==0&&fpri==0) printf("stack");else if(fstack==0&&fque==1&&fpri==0) printf("queue");else if(fstack==0&&fque==0&&fpri==1) printf("priority queue");else printf("not sure");printf("\n");}return 0;}