Complete the function that takes 3 numbers `x, y and k` (where `x ≤ y`), and returns the number of integers within the range `[x..y]` (both ends included) that are divisible by `k`.
More scientifically:  `{ i : x ≤ i ≤ y, i mod k = 0 }`
## Example
Given ```x = 6, y = 11, k = 2``` the function should return `3`, because there are three numbers divisible by `2` between `6` and `11`: `6, 8, 10`
- **Note**: The test cases are very large. You will need a O(log n) solution or better to pass. (A constant time solution is possible.)
def divisible_count(x,y,k):
    mod = x % k
    if mod != 0:
        x += (k - mod)
    y -= y % k
    if x > y:
        return 0
    return (y - x) // k + 1
def divisible_count(x,y,k):
    mod = x % k
    if mod != 0:
        x += (k - mod)
    y -= y % k
    if x > y:
        return 0
    return (y - x) // k + 1