Given two array of integers(the first array is array A, the second array is array B), now we are going to find a element in array A which is A[i], and another element in array B which is B[j], so that the difference between A[i] and B[j] (|A[i] - B[j]|) is as small as possible, return their smallest difference.
Example
For example, given array A = [3,6,7,4], B = [2,8,9,3], return 0
O(n log n) time
public class Solution {
/**
* @param A, B: Two integer arrays.
* @return: Their smallest difference.
*/
public int smallestDifference(int[] A, int[] B) {
// write your code here
if(A.length==0 ||A==null ||B.length==0||B==null) return 0;
int min=Integer.MAX_VALUE;
Arrays.sort(B);
for(int i=0;i<A.length;i++)
{
int key=A[i];
int l=0;
int r=B.length-1;
while(l<r)
{
int mid=(l+r)/2;
if(key==B[mid]) return 0;
else if(key>B[mid])
{
l=mid+1;
}
else
{
r=mid-1;
}
min=Math.min(min,Math.abs(key-B[mid]));
}
if(l==r)
{
min=Math.min(min,Math.abs(key-B[l]));
}
}
return min;
}
}
原文：http://www.cnblogs.com/kittyamin/p/5132206.html