Given two array of integers(the first array is array A, the second array is arrayB), 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。

分析：

首先sort, 然后用两个指针分别指向两个array的头部，谁小移动谁。

1 public class Solution { 2     /** 3      * @param A, B: Two integer arrays. 4      * @return: Their smallest difference. 5      */ 6     public int smallestDifference(int[] A, int[] B) { 7         Arrays.sort(A); 8         Arrays.sort(B); 9         10         int pa = 0; 11         int pb = 0;12         13         int diff = Integer.MAX_VALUE;14         15         while (pa < A.length && pb < B.length) {16             if (A[pa] < B[pb]) {17                 diff = Math.min(diff, Math.abs(A[pa] - B[pb]));18                 pa++;19             } else if (A[pa] == B[pb]) {20                 return 0;21             } else {22                 diff = Math.min(diff, Math.abs(A[pa] - B[pb]));23                 pb++;24             }25         }26         return diff;27     }28 }