double findMedianSortedArrays(int A[], int m, int B[], int n) {
if((m+n)%2==1)
return (double)findKthElement(A,m,B,n,(m+n)/2+1);
else{
int a=findKthElement(A,m,B,n,(m+n)/2);
int b=findKthElement(A,m,B,n,(m+n)/2+1);
return ((double)a+(double)b)/2.0;
}
}
int findKthElement(int *nums, int startIndex,int endIndex, int k){
if(startIndex == endIndex) return nums[k];
int idx = RandSelectElement(nums, startIndex, endIndex);
int kk = idx - startIndex + 1;
if(kk < k){
return findKthElement(nums, idx+1, endIndex,k-kk);
}
else if (kk > k){
return findKthElement(nums, startIndex, idx,k);
}
return nums[idx];
}
int findKthElement(int A[],int m,int B[],int n,int k){
if(m>n)
return findKthElement(B,n,A,m,k);
if(m==0){
return B[k-1];
}
if(k==1)
return Min(A[0],B[0]);
int countA=Min(k/2,m);
int countB=k-countA;
if(A[countA-1]<B[countB-1])
return findKthElement(A+countA,m-countA,B,n,k-countA);
else if(A[countA-1]==B[countB-1])
return A[countA-1];
else
return findKthElement(A,m,B+countB,n-countB,k-countB);
}
int findKthLargest(int* nums, int numsSize, int k) {
return findKthElement(nums,0,numsSize,numsSize-k+1);
}
