02-线性结构3. Pop Sequence (25)

Given a stack which can keep M numbers at most. Push N numbers in the order of 1, 2, 3, ..., N and pop randomly. Youare supposed to tell if a given sequence of numbers is a possible pop sequence of the stack. For example, if M is 5 and Nis 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 51 2 3 4 5 6 73 2 1 7 5 6 47 6 5 4 3 2 15 6 4 3 7 2 11 7 6 5 4 3 2

Sample Output:

YESNONOYESNO

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继续学习数据结构。

这个题目对我来说有点困难，我竟然不知道有stack这个库，还用vector来模拟，这样会比较烦，比较烦，下次就知道了，还是见识窄啊。

题目的解题思路是简单的，就是比较当前栈的top值，和当前的数值，不相等的话，就一直push进来，直到相等，或者是溢出MaxSize。

code如下：

#include <iostream>#include <stack>/* run this program using the console pauser or add your own getch, system("pause") or input loop */int main(int argc, char** argv) {int MaxSize=0,N=0,K=0;int a[1010];scanf("%d %d %d",&MaxSize,&N,&K);//for(i=0;i<N;i++) v.push_back(i);for(int i=0; i<K; i++){int idx=1;bool flag=true;std::stack<int> s;for(int j=0; j<N; j++){scanf("%d",&a[j]);if(flag){while(s.empty() || s.top() != a[j]){s.push(idx);if(s.size()>MaxSize){flag=false;break;}idx++;}if(flag && s.size()>=1 && s.top()==a[j]) s.pop();}}if(!flag) printf("NO\n");else printf("YES\n");}return 0;}