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Java-based LeetCode algorithm problem solutions, regularly updated

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810\. Chalkboard XOR Game

Hard

You are given an array of integers `nums` represents the numbers written on a chalkboard.

Alice and Bob take turns erasing exactly one number from the chalkboard, with Alice starting first. If erasing a number causes the bitwise XOR of all the elements of the chalkboard to become `0`, then that player loses. The bitwise XOR of one element is that element itself, and the bitwise XOR of no elements is `0`.

Also, if any player starts their turn with the bitwise XOR of all the elements of the chalkboard equal to `0`, then that player wins.

Return `true` _if and only if Alice wins the game, assuming both players play optimally_.

**Example 1:**

**Input:** nums = [1,1,2]

**Output:** false

**Explanation:** 

Alice has two choices: erase 1 or erase 2. 

If she erases 1, the nums array becomes [1, 2]. 

The bitwise XOR of all the elements of the chalkboard is 1 XOR 2 = 3. 

Now Bob can remove any element he wants, because Alice will be the one to erase the last element and she will lose. 

If Alice erases 2 first, now nums become [1, 1]. 

The bitwise XOR of all the elements of the chalkboard is 1 XOR 1 = 0. 

Alice will lose.

**Example 2:**

**Input:** nums = [0,1]

**Output:** true

**Example 3:**

**Input:** nums = [1,2,3]

**Output:** true

**Constraints:**

*   `1 <= nums.length <= 1000`
*   0 <= nums[i] < 2¹⁶