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题目:
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)).
链接: http://leetcode.com/problems/median-of-two-sorted-arrays/
题解：
把题目从find median转换为find k/2 th最小值。注意边界条件当k = 1时取A[0]与B[0]两数中较小者。Time Complexity O(log(m + n))，Space Complexity O(1)
public class Solution {
public double findMedianSortedArrays(int A[], int B[]) {
int len = A.length + B.length;
if(len % 2 == 0)
return (findKth(A, 0, B, 0, len / 2) + findKth(A, 0, B, 0, len / 2 + 1)) / 2.0;
else
return findKth(A, 0, B, 0, len / 2 + 1);
}
private double findKth(int A[], int A_start, int B[], int B_start, int k){
if(A_start >= A.length)
return B[B_start + k - 1];
if(B_start >= B.length)
return A[A_start + k - 1];
if(k == 1)
return Math.min(A[A_start], B[B_start]);
int A_key = A_start + k / 2 - 1 < A.length ? A[A_start + k / 2 - 1] : Integer.MAX_VALUE;
int B_key = B_start + k / 2 - 1 < B.length ? B[B_start + k / 2 - 1] : Integer.MAX_VALUE;
if(A_key < B_key)
return findKth(A, A_start + k / 2, B, B_start, k - k / 2);
else
return findKth(A, A_start, B, B_start + k / 2, k - k / 2);
}
}
Reference:
http://www.cnblogs.com/springfor/p/3861890.html
http://blog.csdn.net/yutianzuijin/article/details/11499917
4. Median of Two Sorted Arrays
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原文地址：http://www.cnblogs.com/yrbbest/p/4430090.html
