pub fn with_len(len: usize) -> Self {
        FenwickTree {
            data: vec![T::default(); len + 1],
        }
    }
/// construct a new FenwickTree with given length
construct a new FenwickTree with given length
construct a new FenwickTree with given length
pub fn with_len(len: usize) -> Self {
        FenwickTree {
            data: vec![T::default(); len + 1],
        }
    }
pub fn with_len ( len : usize ) -> Self { FenwickTree { data : vec ! [ T default ( ) len 1 ] , } }
construct a new FenwickTree with given length
construct a new FenwickTree with given length
len
usize
len
usize