4. Median of Two Sorted Arrays

4. Median of Two Sorted Arrays

题目描述

There are two sorted arrays nums1 and nums2 of size m and n respectively.

Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).

You may assume nums1 and nums2 cannot be both empty.

Example 1:

nums1 = [1, 3]
nums2 = [2]

The median is 2.0
Example 2:

nums1 = [1, 2]
nums2 = [3, 4]

The median is (2 + 3)/2 = 2.5

解题思路，

类似于合并的思想，将两个有序的数组合并即可

class Solution {
    public double findMedianSortedArrays(int[] nums1, int[] nums2) {
        int i = 0,j =0;
        List list3 = new ArrayList<>();
        //汇总两个数组，
        while( i < nums1.length && j < nums2.length){
            if(nums1[i] < nums2[j]){
                list3.add(nums1[i]);
                i++;
            }else if(nums1[i] == nums2[j]){
                list3.add(nums1[i]);
                list3.add(nums2[j]);
                i++;
                j++;
            }else{
                list3.add(nums2[j]);
                j++;
            }
        }
        if(i < nums1.length ){
            for(int k = i ;  k < nums1.length; k++){
                list3.add(nums1[k]);
            }
        }else if(j < nums2.length ){
            for(int k = j ; k < nums2.length; k++){
                list3.add(nums2[k]);
            }
        }

        double result = 0.0;
        //求出中间值
        if(list3.size() % 2 == 0){
            int right = ((list3.size()/2)> 0? list3.size()/2:0);
            int left = right-1;
            //fix me 注意这里这里需要除以2.0 
            result = (list3.get(left)+list3.get(right))/2.0;
        }else{
            int index = (list3.size()/2)> 0? list3.size()/2:0;
            result = list3.get(index);
        }
        return result;
    }
}