【List习题】A1051 Pop Sequence

标签：size   sample   aci   遍历   output   can   bsp   keep   max   

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

思路：

• 定义动态数组v存储待判的序列，定义栈s模拟入栈出栈操作；
• n个数依次进栈，如果栈内个数超过m则break，否则当栈非空时判断栈顶元素和序列中对应位置元素是否相等，相等则弹出否则入栈；
• 最后判断序列是否已经遍历完，如果没有就是NO，否则就是YES

 1 #include <iostream>
 2 #include <stack>
 3 #include <vector>
 4 using namespace std;
 5 int main()
 6 {
 7     int m, n, k;
 8     cin >> m >> n >> k;
 9     for (int i = 0; i < k; i++) {
10         stack<int>s;
11         vector<int>v(n);
12         for (int j = 0; j < n; j++) {
13             cin >> v[j];
14         }
15         int cur=0;//v中元素的下标
16         for (int j = 1; j <= n; j++) {
17             s.push(j);
18             if (s.size() > m)break;
19             while (!s.empty() && s.top() == v[cur]) {
20                 s.pop();
21                 cur++;
22             }
23         }
24         if (cur < n)
25             cout << "NO" << endl;
26         else
27             cout << "YES" << endl;
28     }
29     return 0;
30 }

【List习题】A1051 Pop Sequence

标签：size   sample   aci   遍历   output   can   bsp   keep   max   

原文地址：https://www.cnblogs.com/PennyXia/p/12494301.html