UVA 11995 I Can Guess the Data Structure!

开始按照训练指南上的习题来训练数据结构了。

这道题给出一系列操作，1 x表示加入x，2表示删除元素，根据这些操作来判断是哪个数据结构。

三种数据结构：栈（后进先出），队列（先进先出），优先队列（题目要求是最大堆）

需要注意删除操作，没有元素就不要再pop了。

#include<algorithm>#include<iostream>#include<cstring>#include<cstdio>#include<vector>#include<string>#include<queue>#include<cmath>///LOOP#define REP(i, n) for(int i = 0; i < n; i++)#define FF(i, a, b) for(int i = a; i < b; i++)#define FFF(i, a, b) for(int i = a; i <= b; i++)#define FD(i, a, b) for(int i = a - 1; i >= b; i--)#define FDD(i, a, b) for(int i = a; i >= b; i--)///INPUT#define RI(n) scanf("%d", &n)#define RII(n, m) scanf("%d%d", &n, &m)#define RIII(n, m, k) scanf("%d%d%d", &n, &m, &k)#define RIV(n, m, k, p) scanf("%d%d%d%d", &n, &m, &k, &p)#define RV(n, m, k, p, q) scanf("%d%d%d%d%d", &n, &m, &k, &p, &q)#define RFI(n) scanf("%lf", &n)#define RFII(n, m) scanf("%lf%lf", &n, &m)#define RFIII(n, m, k) scanf("%lf%lf%lf", &n, &m, &k)#define RFIV(n, m, k, p) scanf("%lf%lf%lf%lf", &n, &m, &k, &p)#define RS(s) scanf("%s", s)///OUTPUT#define PN printf("\n")#define PI(n) printf("%d\n", n)#define PIS(n) printf("%d ", n)#define PS(s) printf("%s\n", s)#define PSS(s) printf("%s ", n)///OTHER#define PB(x) push_back(x)#define SZ() size()#define CLR(a, b) memset(a, b, sizeof(a))#define CPY(a, b) memcpy(a, b, sizeof(b))#define display(A, n, m) {REP(i, n){REP(j, m)PIS(A[i][j]);PN;}}using namespace std;typedef long long LL;typedef pair<int, int> P;const int MOD = 100000000;const int INFI = 1e9 * 2;const LL LINFI = 1e17;const double eps = 1e-6;const double pi = acos(-1.0);const int N = 1111;const int M = 11;const int move[8][2] = {0, 1, 0, -1, 1, 0, -1, 0, 1, 1, 1, -1, -1, 1, -1, -1};int s[N];queue<int> q;priority_queue<int> pq;int main(){    //freopen("input.txt", "r", stdin);    //freopen("output.txt", "w", stdout);    int n, a, b, c, t;    bool fs, fq, fpq;    while(RI(n) != EOF)    {        t = 0;        fs = fq = fpq = 1;        while(!q.empty())q.pop();        while(!pq.empty())pq.pop();        REP(i, n)        {            RII(a, b);            if(a == 1)            {                if(fs)s[t++] = b;                if(fq)q.push(b);                if(fpq)pq.push(b);            }            else            {                if(fs)                {                    if(t)                    {                        c = s[--t];                        if(c != b)fs = 0;                    }                    else fs = 0;                }                if(fq)                {                    if(!q.empty())                    {                        c = q.front();                        q.pop();                        if(c != b)fq = 0;                    }                    else fq = 0;                }                if(fpq)                {                    if(!pq.empty())                    {                        c = pq.top();                        pq.pop();                        if(c != b)fpq = 0;                    }                    else fpq = 0;                }            }        }        c = fs + fq + fpq;        if(!c)puts("impossible");        else if(c == 1)        {            if(fs)puts("stack");            if(fq)puts("queue");            if(fpq)puts("priority queue");        }        else puts("not sure");    }    return 0;}