Got asked these in Walmart coding round:

A. Given a number n. To find two numbers a and b such that

     a xor b = n
     b >= a and (b - a) should be minimum
     for all the a and b which satisfy the above conditions a and b should be minimum
     1 <= n <= 1e12

• My Soln: for(j = 0; j <= 62; j++) if((n >> j) & 1) b = (1 << j); a = n - b;
• Result: Partial testcase passed
• Weightage: 20 pts.

B. Given an array A of size n and a number K. Have to find the number of subarrays [l, r] such that:

    (r - l + 1) = K * (sum of all elements of subarray [l, r])
    1 <= n <= 1e5
    |K| >= 1
    -1e6 <= A[i] <= 1e6

• My Soln: Wrote O(n * n) soln. Spoiler Alert got TLE.
• Weightage: 30 pts.

How can I have solved these???