K Closest Numbers In Sorted Array

 1 public class Solution {
 2     /**
 3      * @param A an integer array
 4      * @param target an integer
 5      * @param k a non-negative integer
 6      * @return an integer array
 7      */
 8     public int[] kClosestNumbers(int[] A, int target, int k) {
 9         if (A == null || A.length == 0) {
10             return A;
11         }
12         if (k > A.length) {
13             return A;
14         }
15         
16         int[] result = new int[k];
17         int index = findIndex(A, target);
18         int begin = index - 1, end = index;
19         for (int i = 0; i < k; i++) {
20             if (begin < 0) {
21                 result[i] = A[end++];
22             } else if (end >= A.length) {
23                 result[i] = A[begin--];
24             } else {
25                 if (Math.abs(target - A[begin]) <= Math.abs(A[end] - target)) {
26                     result[i] = A[begin--];
27                 } else {
28                     result[i] = A[end++];
29                 }
30             }
31         }
32         return result;
33     }
34     
35     //find first position which ge target if connot find return A.length - 1
36     private int findIndex(int[] A, int target) {
37         int left = 0, right = A.length - 1;
38         while (left + 1 < right) {
39             int mid = left + (right - left) / 2;
40             if (A[mid] == target) {
41                 right = mid;
42             } else if (A[mid] < target) {
43                 left = mid;
44             } else {
45                 right = mid;
46             }
47         }
48         if (A[left] >= target) {
49             return left;
50         }
51         if (A[right] >= target) {
52             return right;
53         }
54         return A.length - 1;
55     }
56 }