uva - 10730 - Antiarithmetic?(暴力枚举)

#include<cstdio>
#include<vector>
#include<queue>
#include<cmath>
#include<cstring>
#include <cstdlib>
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long LL;

const int maxn = 10100;
int a[maxn],n;
int main()
{
while(scanf("%d",&n)==1&&n){
scanf(":");
for(int i=1;i<=n;i++){
int x;
scanf("%d",&x);
x++;
a[x] = i;
}
bool flag=true;
for(int i=1;i<=n;i++){
for(int j=1;i+2*j<=n;j++){
if( (a[i] < a[j+i] && a[j+i] < a[j+j+i])
||(a[i] > a[j+i] && a[j+i] > a[j+j+i]) )
{flag=false;
break;}
}
if(!flag) break;
}
if(flag) printf("yes\n");
else printf("no\n");
}
return 0;
}