Basic Data Structure HDU

Mr. Frog learned a basic data structure recently, which is called stack.There are some basic operations of stack：

∙

InputThe first line contains only one integer T ( $T \leq 20$ OutputFor each test case, first output one line "Case #x：w, where x is the case number (starting from 1). Then several lines follow, i-th line contains an integer indicating the answer to the i-th QUERY operation. Specially, if the i-th QUERY is invalid, just print " Invalid."(without quotes). (Please see the sample for more details.)
Sample Input

2
8
PUSH 1
QUERY
PUSH 0
REVERSE
QUERY
POP
POP
QUERY
3
PUSH 0
REVERSE
QUERY

Sample Output

Case #1:
1
1
Invalid.
Case #2:
0

Hint

In the first sample： during the first query, the stack contains only one element 1, so the answer is 1. then in the second query, the stack contains 0, l
(from bottom to top), so the answer to the second is also 1. In the third query, there is no element in the stack, so you should output Invalid. 

        
 
给一个栈.有push,pop,query ,reverse这些操作,
对于每个询问输出这个栈从栈顶到底进行题目给的这个运算后的结果;
 $∙$ 



组队训练赛的时候这题我直接扔给队友写的  
队友写的自闭了  不过最后还是出来了
自己赛后补题  补到自闭  
我不适合写模拟


我写了很久 尽量的简化了 模拟过程

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <queue>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <set>
 7 #include <iostream>
 8 #include <map>
 9 #include <stack>
10 #include <string>
11 #include <vector>
12 #define  pi acos(-1.0)
13 #define  eps 1e-6
14 #define  fi first
15 #define  se second
16 #define  lson l,m,rt<<1
17 #define  rson m+1,r,rt<<1|1
18 #define  bug         printf("******
")
19 #define  mem(a,b)    memset(a,b,sizeof(a))
20 #define  fuck(x)     cout<<"["<<x<<"]"<<endl
21 #define  f(a)        a*a
22 #define  sf(n)       scanf("%d", &n)
23 #define  sff(a,b)    scanf("%d %d", &a, &b)
24 #define  sfff(a,b,c) scanf("%d %d %d", &a, &b, &c)
25 #define  sffff(a,b,c,d) scanf("%d %d %d %d", &a, &b, &c, &d)
26 #define  pf          printf
27 #define  FRE(i,a,b)  for(i = a; i <= b; i++)
28 #define  FREE(i,a,b) for(i = a; i >= b; i--)
29 #define  FRL(i,a,b)  for(i = a; i < b; i++)
30 #define  FRLL(i,a,b) for(i = a; i > b; i--)
31 #define  FIN         freopen("DATA.txt","r",stdin)
32 #define  gcd(a,b)    __gcd(a,b)
33 #define  lowbit(x)   x&-x
34 #pragma  comment (linker,"/STACK:102400000,102400000")
35 using namespace std;
36 typedef long long  LL;
37 typedef unsigned long long ULL;
38 const int INF = 0x7fffffff;
39 const int mod = 1e9 + 7;
40 const int maxn = 4e5 + 10;
41 int t, n, a[maxn], L, R, cas = 1, x;
42 char s[10];
43 multiset<int>st;
44 multiset<int>::iterator it;
45 int main() {
46    // FIN;
47     sf(t);
48     while(t--) {
49         st.clear();
50         L = 2e5, R = 2e5;
51         int flag = 1;
52         sf(n);
53         printf("Case #%d:
", cas++);
54         for (int i = 0 ; i < n ; i++) {
55             scanf("%s", s);
56             if (s[0] == 'Q') {
57                 if (L == R) printf("Invalid.
");
58                 else if (st.empty()) printf("%d
",(R-L)%2);
59                 else {
60                     if (flag) {
61                         //fuck((*st.begin()) - L);
62                         printf("%d
", (((*st.begin()) - L) + (*st.begin() != R - 1)) % 2);
63                     } else {
64                         it=st.end();
65                         it--;
66                      //   fuck(L);
67                         printf("%d
", ((R - (*it))-1 + (*it != L)) % 2);
68                     }
69                 }
70             }
71             if (s[0] == 'P' && s[1] == 'U') {
72                 sf(x);
73                 if (flag) a[R++] = x;
74                 else a[--L] = x;
75                 if (!x) {
76                     if (flag)  st.insert(R - 1);
77                     else st.insert(L);
78                 }
79             }
80             if (s[0] == 'P' && s[1] == 'O') {
81                 if (L == R) continue;
82                 if (flag) {
83                     if(!a[R - 1]) st.erase(R - 1);
84                     R--;
85                 } else {
86                     if (!a[L]) st.erase(L);
87                     L++;
88                 }
89             }
90             if (s[0] == 'R') flag ^= 1;
91         }
92     }
93     return 0;
94 }

原文地址：https://www.cnblogs.com/qldabiaoge/p/9520611.html