<pre class="language-javascript"><code class="language-javascript">

/**
 * @param {number[]} arr
 * @returns number
 */
function findSingle(arr) {
 return arr.reduce((prev, curr) =&gt; prev ^ curr, 0)
}
</code></pre>

O(n), O(1)

Given an array of integers, all integers appear twice except one integer, could you quickly target it ? const arr = [10, 2, 2 , 1, 0, 0, 10] findSingl…