#include <iostream>
#include <vector>
#include <deque>
#include <algorithm>
 
using namespace std;
 
int main() {
    int T;
    cin >> T;
 
    while (T--) {
        int n;
        cin >> n;
 
        vector<int> heights(n);
        for (int i = 0; i < n; ++i) {
            cin >> heights[i];
        }
 
        int maxLength = 0;
 
        // 使用滑动窗口方法
        int left = 0;  // 左边界
        for (int right = 0; right < n; ++right) {
            while (heights[right] - heights[left] > (right - left)) {
                left++;  // 调整左边界
            }
            maxLength = max(maxLength, right - left + 1);  // 更新最大长度
        }
 
        cout << maxLength << endl;
    }
 
    return 0;
}
 

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5
3 6 2 3 1
6
1 1 4 5 1 4
10
7 8 3 5 6 1 2 4 9 10