1051 Pop Sequence (25分)

Posted 2020-11-23 57one

Given a stack which can keep M numbers at most. Push N numbers in the order of 1, 2, 3, ..., N and pop randomly. You are supposed to tell if a given sequence of numbers is a possible pop sequence of the stack. For example, if M is 5 and N is 7, we can obtain 1, 2, 3, 4, 5, 6, 7 from the stack, but not 3, 2, 1, 7, 5, 6, 4.

Input Specification:

Each input file contains one test case. For each case, the first line contains 3 numbers (all no more than 1000): M (the maximum capacity of the stack), N (the length of push sequence), and K (the number of pop sequences to be checked). Then K lines follow, each contains a pop sequence of N numbers. All the numbers in a line are separated by a space.

Output Specification:

For each pop sequence, print in one line "YES" if it is indeed a possible pop sequence of the stack, or "NO" if not.

Sample Input:

5 7 5
1 2 3 4 5 6 7
3 2 1 7 5 6 4
7 6 5 4 3 2 1
5 6 4 3 7 2 1
1 7 6 5 4 3 2

Sample Output:

YES
NO
NO
YES
NO
题目分析:一道模拟题 写了半天

 1 #define _CRT_SECURE_NO_WARNINGS
 2 #include <climits>
 3 #include<iostream>
 4 #include<vector>
 5 #include<queue>
 6 #include<map>
 7 #include<set>
 8 #include<stack>
 9 #include<algorithm>
10 #include<string>
11 #include<cmath>
12 using namespace std;
13 stack<int> S1;
14 
15 int main()
16 {
17     int M, N, K;
18     cin >> M >> N >> K;
19     vector<int> Array(N+1);
20     vector<int> Test(N+1);
21     for (int i = 1; i <= N; i++)
22         Array[i] = i;
23     for (int i = 0; i < K; i++)
24     {
25         while (S1.size())
26             S1.pop();
27         for (int j = 1; j <= N; j++)
28             cin >> Test[j];
29         int k = 1, t = 1,flag=1;
30         while (t<=N)
31         {
32             if (S1.size()> M)
33             {
34                 flag = 0;
35                 break;
36             }
37             else if (S1.size())
38             {
39                 if (S1.top() == Test[t])
40                 {
41                     S1.pop();
42                     t++;
43                 }
44                 else if(k<=N)
45                 {
46                     S1.push(Array[k]);
47                     k++;
48                 }
49                 else
50                 {
51                     if (S1.top() == Test[t])
52                     {
53                         S1.pop();
54                         t++;
55                     }
56                     else
57                     {
58                         flag = 0;
59                         break;
60                     }
61                 }
62             }
63             else {
64                 S1.push(Array[k]);
65                 k++;
66             }
67         }
68         if (flag)
69             cout << "YES" << endl;
70         else
71             cout << "NO" << endl;
72     }
73 }

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