Median of Two Sorted Arrays - Partition Approach

Binary search to find the correct partition in both arrays. If you take $i$ elements from nums1 and $j$ elements from nums2 where $i + j = (m + n + 1) / 2$, the median is determined by the boundary elements.

$1.$ Binary search on $i$ (partition point in smaller array).

$2.$ $j = (m + n + 1) / 2 - i$.

$3.$ Valid partition: maxLeft1 <= minRight2 and maxLeft2 <= minRight1.

$4.$ If maxLeft1 > minRight2, decrease $i$. If maxLeft2 > minRight1, increase $i$.