306829: CF1257C. Dominated Subarray
Memory Limit:256 MB
Time Limit:2 S
Judge Style:Text Compare
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Description
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