Leetcode 1470: Shuffle the array

In this Leetcode problem, we try to shuffle the numbers in a array in a particular manner.

Problem statement

Solutions

I am always amazed how simple problems have many interesting solutions!

Solution 1: New array and 3 pointers

class Solution {
    public int[] shuffle(int[] nums, int n) {
        int[] res = new int[2 * n];
        int i = 0;
        int j = n;
        int curr = 0;
        while (i < n) {
            res[curr] = nums[i];
            curr++;
            i++;
            res[curr] = nums[j];
            curr++;
            j++;
        }
        return res;
    }
}

This is short and effective, easy to understand, no problem with that.

Solution 2: In place with replacement while loops

class Solution {
    public int[] shuffle(int[] nums, int n) {
        // in place
        int N = 2 * n;
        for (int i = 1; i < N -1; i++) {
            nums[i] = -nums[i];
        }
        int minNeg = 1;
        while (minNeg < N) {
            if (nums[minNeg] < 0) {
                int index = minNeg;
                int ret = nums[index];
                while(ret < 0) {
                    int newIndex = computeNew(index, n);
                    int newRet = nums[newIndex]…