Zigzag Sort Problem Statement

Given a list of numbers, reorder it in zigzag order.

Let’s say the given list of numbers is numbers. Zigzag order of numbers should follow the following order:
numbers[0] <= numbers[1] >= numbers[2] <= numbers[3]....

Example One

{
"numbers": [3, 5, 6, 1, 4, 2]
}

Output:

[3, 6, 1, 5, 2, 4]

Explanation: [2, 5, 3, 4, 1, 6] is also accepted.

Example Two

{
"numbers": [3, 1, 3, 1, 2, 4]
}

Output:

[1, 3, 1, 3, 2, 4]

Notes

Constraints:

• 1 <= size of the input list <= 2×10⁶
• 10^-3 <= any element of the input list <= 10³

Code For Zigzag Sort Solution: One Pass

/*
Asymptotic complexity in terms of number of elements `n`:
* Time: O(n).
* Auxiliary space: O(1).
* Total space: O(n).
*/

vector<int> zigzag_sort(vector<int> &numbers) {
    for (int i = 0; i + 1 < (int)numbers.size(); i++) {
        if (i % 2 == 0 && numbers[i] > numbers[i + 1]) {
            swap(numbers[i], numbers[i + 1]);
        }
        else if (i % 2 == 1 && numbers[i] < numbers[i + 1]) {
            swap(numbers[i], numbers[i + 1]);
        }
    }
    return numbers;
}

We hope that these solutions to zigzag sort problem have helped you level up your coding skills. You can expect problems like these at top tech companies like Amazon and Google.

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