【Data Structures and Algorithms】7-3 Pop Sequence（25 分）
7-3 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 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：
一个数N，pop之前，1~N都要被push到堆栈里，这时需要判断堆栈是否溢出，以及之后的输出顺序是否正确。
PS：提供一组测试数据，一开始没有考虑到这种情况，没有加flag判断，所以过不了：(
4 6 1
3 1 2 6 5 4
#include
#include
#define MaxSize 1003
typedef int Data[MaxSize];
typedef struct SNode* PtrtoSNode;
typedef PtrtoSNode Stack;
struct SNode {
int top;
int size;
Data seq;
};
int Push(Stack S,int a) {
if(S->topsize) {
S->seq[S->top++]=a;
return 1;
}
else return 0;
}
int pop(Stack S) {
if(S->top)
return S->seq[--S->top];
else return 0;
}
int main() {
int M,N,K,i,j,temp,now,flag;
Stack S=(Stack)malloc( sizeof(struct SNode) );
scanf("%d %d %d",&M,&N,&K);
S->size=M;
//freopen("d:\\result.txt","w",stdout);
for(i=0;itop=0;
now=1;
flag=1;
for(j=0;j