4. Median of Two Sorted Arraysm.java

class Solution {
    public double findMedianSortedArrays(int[] nums1, int[] nums2) {
        if (nums2.length < nums1.length){
            return findMedianSortedArrays(nums2, nums1);
        }
        int n1 = nums1.length;
        int n2 = nums2.length;
        int low = 0, high = n1;
        while (low <= high){
            int cut1 = low + (high - low)/2;
            int cut2 = ((n1 + n2 + 1)/2) - cut1;
            int left1 = cut1 == 0 ? Integer.MIN_VALUE : nums1[cut1-1];
            int left2 = cut2 == 0 ? Integer.MIN_VALUE : nums2[cut2-1];
            
            int right1 = cut1 == n1 ? Integer.MAX_VALUE : nums1[cut1];
            int right2 = cut2 == n2 ? Integer.MAX_VALUE : nums2[cut2];
            
            if (left1 <= right2 && left2 <= right1){
                if ((n1+n2)%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 -1;
    }
}