4.Median of Two Sorted Arrays

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题目：Median of Two Sorted Arrays

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)).

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

超时的实现：

double findMedianSortedArrays(int* nums1, int nums1Size, int* nums2, int nums2Size) {        int num=nums1Size+nums2Size;                double ret=0;                int i=0,j=0;                quicksort(nums1,0,nums1Size-1);        quicksort(nums2,0,nums2Size-1);                for(i=0;i<nums1Size;i++)        {            printf("%d ",nums1[i]);        }                if(num%2==0)        {            num=num>>1;            if(num<nums1Size)            {                ret=(nums1[num]+nums1[num-1])/2.0;            }            else if(nums1[num-1] == nums1[nums1Size-1])            {                ret=(nums1[num-1]+nums2[0])/2.0;            }            else if((num-1)>=nums1Size)            {                ret=(nums2[num-nums1Size-1]+nums2[num-nums1Size])/2.0;            }        }        else        {            num=num>>1;            if(num<nums1Size)            {                ret=nums1[num];            }            else            {                ret=nums2[num-nums1Size];            }                    }          return ret;}void quicksort(int* v, int left, int right){        if(left < right){                int key = v[left];                int low = left;                int high = right;                while(low < high){                        while(low < high && v[high] > key){                                high--;                        }                        v[low] = v[high];                        while(low < high && v[low] < key){                                low++;                        }                        v[high] = v[low];                }                v[low] = key;                quicksort(v,left,low-1);                quicksort(v,low+1,right);        }}

别人的实现：

double searchKth(int* a,int m,int* b,int n,int k){    printf("The k is %d %d %d\n",k,m,n);        if(m > n) // m is always the smmaller    {        return searchKth(b,n,a,m,k);    }        if(m==0)    {        return b[k-1];    }        if(k==1)    {        printf(" a[0] %d, b[0] %d\n",a[0],b[0]);        if(a[0]<=b[0])        {            return a[0];        }        else            return b[0];    }        int p=0,q=0;    if((k/2)<=m)        p=k/2;    else        p=m;        q=k-p;        printf("%d %d\n",p,q);    if(a[p-1] < b[q-1])        return searchKth(a+p,m-p,b,n,k-p);    else if(a[p-1] > b[q-1])        return searchKth(a,m,b+q,n-q,k-q);    else        return a[p-1];}double findMedianSortedArrays(int* nums1, int nums1Size, int* nums2, int nums2Size) {    int sum=nums1Size+nums2Size;    if(sum & 0x1)//奇数    {        return searchKth(nums1,nums1Size,nums2,nums2Size,sum/2+1);    }    else    {        double t=searchKth(nums1,nums1Size,nums2,nums2Size,sum/2)+searchKth(nums1,nums1Size,nums2,nums2Size,sum/2+1);        return t/2;    }}

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