Codeforces Round 825 (Div. 2)
C1
Good Subarrays (Easy Version)
Codeforces
1300
原题
← BC2 →
翻译中…

This is the easy version of this problem. In this version, we do not have queries. Note that we have multiple test cases in this version. You can make hacks only if both versions of the problem are solved.

翻译中…

An array $b$ of length $m$ is good if for all $i$ the $i$-th element is greater than or equal to $i$. In other words, $b$ is good if and only if $b_i \geq i$ for all $i$ ($1 \leq i \leq m$).

翻译中…

You are given an array $a$ consisting of $n$ positive integers. Find the number of pairs of indices $(l, r)$, where $1 \le l \le r \le n$, such that the array $[a_l, a_{l+1}, \ldots, a_r]$ is good.

翻译中…

Input

翻译中…

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \leq t \leq 2 \cdot 10^5$). Description of the test cases follows.

翻译中…

The first line of each test case contains an integer $n$ ($1 \leq n \leq 2 \cdot 10^5$), the length of the array $a$.

翻译中…

The second line of each test case contains $n$ space-separated integers $a_1,a_2,\ldots,a_n$ ($1 \leq a_i \leq n$), representing the array $a$.

翻译中…

It is guaranteed that the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$.

翻译中…

Output

翻译中…

For each test case, print the number of suitable pairs of indices.

翻译中…

Note

翻译中…

In the first test case, all subarrays of $a$ are good, so all pairs are suitable.

翻译中…

In the second test case, the pairs $(1, 1)$, $(2, 2)$, and $(3, 3)$ are suitable. For example, when $(l, r) = (1, 2)$, the array $b=[1,1]$ is not good because $b_2 \lt 2$.

翻译中…

样例

Input #1
3
3
1 2 3
3
1 1 1
4
2 1 4 3
Output #1
6
3
7
InputCopy OutputCopy
题目信息
题号
1736C1
时间限制
1 s
内存限制
256 MB
标签
二分
数据结构
调度
双指针

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。