#include<stdio.h>bool check(int a[],int start,int end);void main(){//	int a[]={5,7,6,9,11,10,8};	int a[]={7,4,6,5};	int len=sizeof(a)/sizeof(int);	if(check(a,0,len-1))		printf("ok\n");	else printf("not ok\n");}bool check(int a[],int start,int end){	if(end==start)		return 1;	int s=start,e=end;	while(s<e && a[s]<=a[end])		s++;	if(s==e)		return 1;	int newend=s-1;	while(s<e && a[s]>=a[end])		s++;	if(s<e || s==e && a[s]<a[end])		return 0;	bool one,two;	one=check(a,start,newend);	two=check(a,newend+1,end-1);	return one & two;}