Given a positive integer n, find first k digits after the decimal in the value of 1/n and return it as a string.

Note: Your program should avoid overflow and floating-point arithmetic.

Example 1:

Input: n = 3, k = 3
Output: 333
Explanation: 1/3=0.33333, so
after point 3 digits are 3,3,3.

â€‹Example 2:

Input: n = 50, k = 4
Output: 0200
Explanation: 1/50=0.020000, so
after point 4 digits are 0,2,0,0.

Your Task:
You don't need to read input or print anything. Your task is to complete the function Kdigits() which takes n, k as inputs and returns the string.

Expected Time Complexity: O(k) Expected Auxiliary Space: O(1)