# 判断出栈序列是否合法（c语言实现）

### 题目

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.

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

YES
NO
NO
YES
NO

### 代码

``````#include <stdio.h>
#define maxn 1005
int stack[maxn];
int out[maxn];
int check(int m,int n)
{
int po=0,top=0;
for(int i=1;i<=n;i++)
{
for(int j=po+1;j<=out[i];j++)
{
po=j;
stack[top++]=j;
if(top>m) return 0;
}
if(stack[--top]!=out[i])
return 0;
}
return 1;
}
int main()
{
int m,n,k;
scanf("%d %d %d",&m,&n,&k);
while(k--){
for(int i=1;i<=n;i++){
scanf("%d",&out[i]);
}
if(check(m,n))
printf("YES\n");
else
printf("NO\n");
}
return 0;
}

``````

### 结果 原文作者：Sicilly_琬姗
原文地址: https://blog.csdn.net/weixin_37551036/article/details/98188528
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