HDU3833——哈希——YY's new problem

/************************************************
* Author        :Powatr
* Created Time  :2015-9-2 13:38:52
* File Name     :
************************************************/

#include <cstdio>
#include <algorithm>
#include <iostream>
#include <sstream>
#include <cstring>
#include <cmath>
#include <string>
#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <bitset>
#include <cstdlib>
#include <ctime>
using namespace std;

#define lson l, mid, rt << 1
#define rson mid + 1, r, rt << 1 | 1
typedef long long ll;
const int MAXN = 1e5 + 10;
const int INF = 0x3f3f3f3f;
const int MOD = 1e9 + 7;

int a[MAXN];
int _hash[MAXN];
int main(){
int T;
int n;
for(scanf("%d", &T); T--; ){
scanf("%d", &n);
memset(_hash, 0, sizeof(_hash));
for(int i = 1; i <= n; i++){
scanf("%d", &a[i]);
_hash[a[i]] = i;
}
int flag = 0;
for(int i = 1; i <= n; i++){
for(int j = i + 1; j <= n; j++){
int sum = a[i] + a[j];
if(sum % 2 == 1) continue;
sum /= 2;
if(_hash[sum] > i && _hash[sum] < j){
flag = 1;
break;
}
}
if(flag) break;
}
printf("%s\n", flag ? "Y" : "N");
}
return 0;
}