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[UVA] 11995 - I Can Guess the Data Structure! [STL应用]
11995 - I Can Guess the Data Structure!
Time limit: 1.000 seconds
Problem I
I Can Guess the Data Structure!
There is a bag-like data structure, supporting two operations:
1 x
Throw an element x into the bag.
2
Take out an element from the bag.
Given a sequence of operations with return values, you‘re going to guess the data structure. It is a stack (Last-In, First-Out), a queue (First-In, First-Out), a priority-queue (Always take out larger elements first) or something else that you can hardly imagine!
Input
There are several test cases. Each test case begins with a line containing a single integer n (1<=n<=1000). Each of the next n lines is either a type-1 command, or an integer 2 followed by an integer x. That means after executing a type-2 command, we get an element x without error. The value of x is always a positive integer not larger than 100. The input is terminated by end-of-file (EOF). The size of input file does not exceed 1MB.
Output
For each test case, output one of the following:
stack
It‘s definitely a stack.
queue
It‘s definitely a queue.
priority queue
It‘s definitely a priority queue.
impossible
It can‘t be a stack, a queue or a priority queue.
not sure
It can be more than one of the three data structures mentioned above.
Sample Input
61 11 21 32 12 22 361 11 21 32 32 22 121 12 241 21 12 12 271 21 51 11 32 51 42 4
Output for the Sample Input
queuenot sureimpossiblestackpriority queue
Rujia Liu‘s Present 3: A Data Structure Contest Celebrating the 100th Anniversary of Tsinghua University
Special Thanks: Yiming Li
Note: Please make sure to test your program with the gift I/O files before submitting!
题解：STL中 queue、stack、priority_queue的使用。
代码：
1 #include<cstdio> 2 #include<cstring> 3 #include<stdbool.h> 4 #include<cmath> 5 #include<queue> 6 #include<stack> 7 #include<algorithm> 8 9 10 #define rep(i,a,b) for(i=(a);i<=(b);i++)11 #define red(i,a,b) for(i=(a);i>=(b);i--)12 #define clr(x,y) memset(x,y,sizeof(x))13 #define sqr(x) ((x)*(x))14 15 using namespace std;16 17 int i,j,x,y,pri,qui,sti;18 19 void check()20 {21 if(qui==1 && pri==0 && sti==0) printf("queue\n");22 else23 if(qui==0 && pri==1 && sti==0) printf("priority queue\n");24 else25 if(qui==0 && pri==0 && sti==1) printf("stack\n");26 else27 if(qui==0 && pri==0 && sti==0) printf("impossible\n");28 else29 printf("not sure\n"); 30 }31 32 int main()33 {34 int T;35 36 37 38 while(scanf("%d",&T)!=EOF) {39 pri=qui=sti=1;40 41 queue <int> Q;42 stack <int> S;43 priority_queue <int> prQ;44 45 while(T--) {46 scanf("%d%d",&x,&y);47 if(x==1) {48 Q.push(y);49 S.push(y);50 prQ.push(y);51 } 52 else {53 54 if(qui==1) {55 if(Q.empty() || Q.front()!=y) qui=0;56 if(!Q.empty()) Q.pop();57 }58 59 if(sti==1) {60 if(S.empty() || S.top()!=y) sti=0;61 if(!S.empty()) S.pop();62 } 63 64 if(pri==1) {65 if(prQ.empty() || prQ.top()!=y) pri=0;66 if(!prQ.empty()) prQ.pop();67 } 68 } 69 }70 71 check();72 }73 74 return 0;75 }
[UVA] 11995 - I Can Guess the Data Structure! [STL应用]