Rotate and delete

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Time: O(n^2)

Space: O(n)

Intuition

Alternating operations: rotate array and delete specific element. Simulate rounds.

Algorithm

1In each round i: rotate right by 1, delete element at position n-i (1-indexed). Repeat until one remains.

Common Pitfalls

•Simulate O(n^2). Use deque for efficient rotation and deletion.

Rotate and delete.java

Java

// Approach: Simulate the process: rotate array and delete specified element per round.
// Time: O(n^2) Space: O(n)
class Solution {
    public static int rotateDelete(ArrayList<Integer> arr) {
        boolean flag = true;
        int n = arr.size();
        int x = n / 2;

        while (x != 0) {
            if (flag) {
                n -= 1;
                flag = false;
            } else {
                n -= 2;
                flag = true;
            }
            x--;
        }
        return arr.get(n);
    }
}

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