leetcode 004 Median of Two Sorted Arrays(java)

Median of Two Sorted Arrays

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Question

Total Accepted: 75699 Total Submissions: 428881 Difficulty: Hard

 

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)).

 

参考别人的代码http://www.cnblogs.com/duanqiong/p/4415049.html

 

public class Solution {
     public static double findMedianSortedArrays(int[] nums1, int[] nums2) {
         int len1=nums1.length;
         int len2=nums2.length;
         int totalLength=len1+len2;
         int k=totalLength/2+1;
         if(totalLength%2==1){                                                            //总长度为奇数
             return findKth(nums1,0,len1,nums2,0,len2,k);
         }
         else{                                                                            //总长度为偶数
             return (findKth(nums1,0,len1,nums2,0,len2,k-1)+findKth(nums1,0,len1,nums2,0,len2,k))/2;
         }
        }
     public static double findKth(int num1[],int begin1,int len1,int num2[],int begin2,int len2,int k){
         if(len1>len2)                                    
             return findKth(num2, begin2, len2, num1, begin1, len1, k);                    //确保len1<len2
         if(len1==0)
             return num2[begin2+k-1];
         if(k==1)
             return Math.min(num1[begin1], num2[begin2]);
         
         int tmp1=Math.min(k/2, len1);
         int tmp2=k-tmp1;
         
         if(num1[begin1+tmp1-1]<num2[begin2+tmp2-1])
             return findKth(num1, begin1+tmp1, len1-tmp1, num2, begin2, len2, k-tmp1);
         else if(num1[begin1+tmp1-1]>num2[begin2+tmp2-1])
             return findKth(num1, begin1, len1, num2, begin2+tmp2, len2-tmp2, k-tmp2);
         else
             return num1[begin1+tmp1-1];
     }
     public static void main(String[] args) {
        int[] a={1};
        int[] b={1};
        double median=findMedianSortedArrays(a,b);
        System.out.println(median);
    }
}