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:
|
1 2 3 4 5 6 |
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:
|
1 2 3 4 5 |
YES NO NO YES NO |
代码如下：
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#include<stdio.h> #include<stdlib.h> typedef struct stack_ { int size; int capacity; int top; int *data; } stack; #define is_stack_full(X) ((X)->size==(X)->capacity) #define is_stack_empty(X) (!((X)->size)) #define ptr_top(X) ((X)->data[(X)->top]) stack *inti_stack(int n) { stack *temp; temp=(stack *)malloc(sizeof(stack)); temp->size=0; temp->capacity=n; temp->top=-1; temp->data=(int *)malloc(n*sizeof(int)); return temp; } int push(stack *s,int data) { if(s->size==s->capacity) { return 1; } (s->top)++; (s->size)++; s->data[s->top]=data; return 0; } int pop(stack *s,int *data) { if(s->size==0) { *data=-1; return 1; } *data=s->data[s->top]; (s->size)--; (s->top)--; return 0; } int reset_stack(stack *s) { s->top=-1; s->size=0; return 0; } int delete_stack(stack *s) { free(s->data); free(s); return 0; } int main() { int i,j,m,n,k,sequence,temp,end; char buf[50000]; stack *s; scanf("%d%d%d",&m,&n,&k); //sequence=(int *)malloc(n*sizeof(int)); s=inti_stack(m); for(i=0;i<k;i++) { sequence=1; end=0; for(j=0;j<n;j++) { scanf("%d",&temp); if(s->size>0&&s->data[s->top]==temp) { pop(s,&temp); continue; } if(sequence>n) { gets(buf); printf("NO\n"); goto end; } while(temp!=sequence) { push(s,sequence); sequence++; if(is_stack_full(s)) { gets(buf); printf("NO\n"); goto end; } } sequence++; } printf("YES\n"); end: reset_stack(s); } } |