The Smallest Difference

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

Challenge

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;    }}