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
#include<stdio.h> #include<stdlib.h> typedef int ElemType; typedef struct Stack { ElemType *data; int top; }NodeStack,*qStack; int CreateStack(qStack *q, int number); int Add(qStack *q, ElemType X, int number); ElemType Delet(qStack *q); int main() { int X, Y, Z; scanf("%d %d %d", &X, &Y, &Z); int **a = (int **)malloc(sizeof(ElemType *)*Z); for (int i = 0;i < Z;i++) { a[i] = (int *)malloc(sizeof(ElemType)*Y); } for (int i = 0;i <Z;i++) { for (int j = 0;j < Y;j++) { scanf("%d", &a[i][j]); } } for (int i = 0;i < Z;i++) { int Aold = 1, Anow = 0, number = 0; qStack q = NULL; CreateStack(&q, X); for (int j = 0;j < Y;j++) { Anow = a[i][j]; if (Anow >= Aold) { while (Aold <= Anow) { if (Add(&q, Aold, X) != 1) { break; } Aold++; } number = Delet(&q); } else { number = Delet(&q); } if (number != Anow) { printf("NO"); break; } } if (number == Anow) { printf("YES"); } free(q); if (i != Z - 1) { printf("\n"); } } return 0; } int CreateStack(qStack *q,int number) { int states = 0; if (*q == NULL) { *q = (NodeStack*)malloc(sizeof(NodeStack)); (*q)->data = (ElemType*)malloc(sizeof(ElemType)*number); (*q)->top = -1; states = 1; } return states; } int Add(qStack *q, ElemType X,int number) { int states = 0; if (*q) { if ((*q)->top != number - 1) { (*q)->top++; (*q)->data[(*q)->top]=X; states = 1; } } return states; } ElemType Delet(qStack *q) { ElemType X = -1; if (*q) { if ((*q)->top != -1) { X = (*q)->data[(*q)->top]; (*q)->top--; } } return X; }