- Time limit: 1.00 s
- Memory limit: 512 MB
The first input line has an integer $n$: the size of the array. The array elements are numbered $1,2,\dots,n$.
The next line has $n$ integers $x_1,x_2,\dots,x_n$: the contents of the array.
First print an integer $k$: the number of reversals.
After that, print $k$ lines that describe the reversals. Each line has two integers $a$ and $b$: you reverse a subarray from position $a$ to position $b$.
- $1 \le n \le 2 \cdot 10^5$
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