About the space needed for segment tree, i came across the following equation

N = (ceil)((log(N) / log(2)) + 1)

size = 1 << N

interesting part is , the formula used natural logarithms, i.e, base ‘e’. I also read that upper limit of space required for segment tree is (4 * size of array)

- How to justify/derive this formula
- How this formula maximum value is 4 ?