leetcode: Search Insert Position

given a sorted array and a target value, return the index if the target is

found. if not, return the index where it would be if it were inserted in

order.

you may assume no duplicates in the array.

here are few examples.

<code>[1,3,5,6]</code>, 5 →

2

<code>[1,3,5,6]</code>, 2 → 1

<code>[1,3,5,6]</code>, 7 →

4

<code>[1,3,5,6]</code>, 0 → 0