[Failed] First thought of solution

Given two arrays, find the k th smallest number.
If A[k/2] < B[k/2], then A[0] … A[k/2] will be strictly less than
median; likewise B[k/2+1] … B[end] will be strictly larger than median.
So we can ignore these two parts. Search in the rest part with (k -
num1 - num2) th smallest number