4.java

class Solution {
    public double findMedianSortedArrays(int[] nums1, int[] nums2) {
        if(nums1.length > nums2.length)
            return findMedianSortedArrays(nums2, nums1);
        
        int m = nums1.length;
        int n = nums2.length;
        
        int low = 0, high = m;
        
        while(low <= high){
            int cut1 = (low + high) / 2;
            int cut2 = (m + n + 1) / 2 - cut1;
            
            int left1 = (cut1 == 0) ? Integer.MIN_VALUE : nums1[cut1 - 1];
            int right1 = (cut1 == m) ? Integer.MAX_VALUE : nums1[cut1];
            
            int left2 = (cut2 == 0) ? Integer.MIN_VALUE : nums2[cut2 - 1];
            int right2 = (cut2 == n) ? Integer.MAX_VALUE : nums2[cut2];
            
            if(left1 <= right2 && left2 <= right1){
                if((m + n) % 2 == 0)
                    return (Math.max(left1, left2) + Math.min(right1, right2)) / 2.0;
                else
                    return Math.max(left1, left2);
            }
            else if(left1 > right2)
                high = cut1 - 1;
            else
                low = cut1 + 1;
        }
        
        return 0.0;
    }
}