Pop Sequence

02-线性结构4 Pop Sequence   (25分)

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 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
//题目的意思： //栈的大小M，输入序列的长度N（默认序列即为1,2,3…,N,入栈也是这个顺序），出栈的顺序不定。有K个测试序列，判断每一个测试序列是否是可能的出栈顺序//此题考查堆栈的用法，一堆数按照1，2，3，4....N的顺序入栈//如果第M个数要出栈，则前面一定有M-1个数入栈。#include <stdio.h>#include <stdlib.h>int main(){    int stack[1005];    int top;    int m,n,k;    scanf("%d%d%d",&m,&n,&k);    for(int i=1;i<=k;i++){        top=0;        int flag=1;        int now=1;        int number;        for(int j=1;j<=n;j++){            scanf("%d",&number);            while(flag&&(top==0||stack[top]!=number)){                stack[++top]=now;                if(top>m){                    flag=0;                    break;                }                now++;            }            if(flag&&top>=1&&stack[top]==number)                top--;        }        if(flag)            printf("YES\n");        else            printf("NO\n");    }    return 0;}