There are two sorted arrays A and B 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)).
Solution :O(log(m+n))
// This is reference from Internet and I think it is good enough
public class Solution { public double findMedianSortedArrays(int A[], int B[]) { int m = A.length; int n = B.length; if ((m + n) % 2 != 0) return findKth(A, B, (m + n) / 2, 0, m - 1, 0, n - 1); else { return (findKth(A, B, (m + n) / 2, 0, m - 1, 0, n - 1) + findKth(A, B, (m + n) / 2 - 1, 0, m - 1, 0, n - 1))/2; } } public double findKth(int A[], int B[], int k, int aStart, int aEnd, int bStart, int bEnd){
int aLen = aEnd - aStart + 1;
int bLen = bEnd - bStart + 1;
// Handle special cases
if (aLen == 0)
return B[bStart + k];
if (bLen == 0)
return A[aStart + k];
if (k == 0)
return A[aStart] < B[bStart] ? A[aStart] : B[bStart];
int aMid = aLen * k / (aLen + bLen); // a's middle count
int bMid = k - aMid - 1; // b's middle count
// make aMid and bMid to be array index
aMid = aMid + aStart;
bMid = bMid + bStart;
if (A[aMid] > B[bMid]) {
k = k - (bMid - bStart + 1);
aEnd = aMid;
bStart = bMid + 1;
} else {
k = k - (aMid - aStart + 1);
bEnd = bMid;
aStart = aMid + 1;
}
return findKth(A, B, k, aStart, aEnd, bStart, bEnd);
}
}
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