Dominated Subarray

题意翻译

题目共有 $T$ 次询问。 给出一个长度为 $n$ 的序列，判断是否存在一个连续的子序列，使得这一子序列中只有唯一的众数。 若有，输出最短的可能的子序列长度；若无输出 $-1$。 数据范围： $T \leq 1000$，$1 \leq n \leq 2\times10^5$，$1 \leq a_i \leq n$，$\Sigma^{T}_{i=1}{n} \leq 2\times10^5$.

题目描述

Let's call an array $ t $ dominated by value $ v $ in the next situation. At first, array $ t $ should have at least $ 2 $ elements. Now, let's calculate number of occurrences of each number $ num $ in $ t $ and define it as $ occ(num) $ . Then $ t $ is dominated (by $ v $ ) if (and only if) $ occ(v) > occ(v') $ for any other number $ v' $ . For example, arrays $ [1, 2, 3, 4, 5, 2] $ , $ [11, 11] $ and $ [3, 2, 3, 2, 3] $ are dominated (by $ 2 $ , $ 11 $ and $ 3 $ respectevitely) but arrays $ [3] $ , $ [1, 2] $ and $ [3, 3, 2, 2, 1] $ are not. Small remark: since any array can be dominated only by one number, we can not specify this number and just say that array is either dominated or not. You are given array $ a_1, a_2, \dots, a_n $ . Calculate its shortest dominated subarray or say that there are no such subarrays. The subarray of $ a $ is a contiguous part of the array $ a $ , i. e. the array $ a_i, a_{i + 1}, \dots, a_j $ for some $ 1 \le i \le j \le n $ .

输入输出格式

输入格式

The first line contains single integer $ T $ ( $ 1 \le T \le 1000 $ ) — the number of test cases. Each test case consists of two lines. The first line contains single integer $ n $ ( $ 1 \le n \le 2 \cdot 10^5 $ ) — the length of the array $ a $ . The second line contains $ n $ integers $ a_1, a_2, \dots, a_n $ ( $ 1 \le a_i \le n $ ) — the corresponding values of the array $ a $ . It's guaranteed that the total length of all arrays in one test doesn't exceed $ 2 \cdot 10^5 $ .

输出格式

Print $ T $ integers — one per test case. For each test case print the only integer — the length of the shortest dominated subarray, or $ -1 $ if there are no such subarrays.

输入输出样例

输入样例 #1

4
1
1
6
1 2 3 4 5 1
9
4 1 2 4 5 4 3 2 1
4
3 3 3 3

输出样例 #1

-1
6
3
2

说明

In the first test case, there are no subarrays of length at least $ 2 $ , so the answer is $ -1 $ . In the second test case, the whole array is dominated (by $ 1 $ ) and it's the only dominated subarray. In the third test case, the subarray $ a_4, a_5, a_6 $ is the shortest dominated subarray. In the fourth test case, all subarrays of length more than one are dominated.