how to find the minimum value of z in the range l to r such that (x & z).(y & z) is maximum

Question

For eg:- if x=11,y=21,l=16 and r=21,then the minimum value of z satisfying the question's condition in the range l to r is 19 ie (11 & 19).(21 & 19) is maximum

i can't figure out how to solve this question for large range

Answer 1

Pseudo-code:

    pos = 0 //current position of largest (x&z)(y&z)
    largest = -1
    for z = 1 to r do
        candidate = (x&z)(y&z)
        if candidate > largest then
            largest = candidate
            pos = z
    //result is pos here