Interleaving Positive and Negative Numbers

Given an array with positive and negative integers. Re-range it to interleaving with positive and negative integers.

 Notice

You are not necessary to keep the original order of positive integers or negative integers.

Have you met this question in a real interview? 

Yes

Example

Given [-1, -2, -3, 4, 5, 6], after re-range, it will be [-1, 5, -2, 4, -3, 6] or any other reasonable answer.

java

public class Solution {    /*     * @param A: An integer array.     * @return: nothing     */    public void rerange(int[] A) {        // write your code here        if (A == null || A.length == 0) {            return;        }        Arrays.sort(A);        if (A.length % 2 == 0) {            int left = 1;            int right = A.length - 2;            while (left <= right) {                swap(A, left, right);                left += 2;                right -= 2;            }        } else if (A[(A.length - 1) / 2] < 0) {            int left = 1;            int right = A.length - 1;            while (left <= right) {                swap(A, left, right);                left += 2;                right -= 2;            }        } else {            sort(A, 0, A.length - 1);            int left = 1;            int right = A.length - 1;            while (left <= right) {                swap(A, left, right);                left += 2;                right -= 2;            }        }    }    private void sort(int[] nums, int start, int end) {        if (start > end) {            return;        }        int left = start;        int right = end;        int pivot = nums[(start + end) / 2];        while (left <= right) {            while (left <= right && nums[left] > pivot) {                left++;            }            while (left <= right && nums[right] < pivot) {                right--;            }            if (left <= right) {                int temp = nums[left];                nums[left] = nums[right];                nums[right] = temp;                left++;                right--;            }        }        sort(nums, start, right);        sort(nums, left, end);    }    private void swap(int[] nums, int left, int right) {        int temp = nums[left];        nums[left] = nums[right];        nums[right] = temp;    }}