Largest Perimeter Triangle
<p>Given an integer array <code>nums</code>, return <em>the largest perimeter of a triangle with a non-zero area, formed from three of these lengths</em>. If it is impossible to form any triangle of a non-zero area, return <code>0</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> nums = [2,1,2]
<strong>Output:</strong> 5
<strong>Explanation:</strong> You can form a triangle with three side lengths: 1, 2, and 2.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [1,2,1,10]
<strong>Output:</strong> 0
<strong>Explanation:</strong> 
You cannot use the side lengths 1, 1, and 2 to form a triangle.
You cannot use the side lengths 1, 1, and 10 to form a triangle.
You cannot use the side lengths 1, 2, and 10 to form a triangle.
As we cannot use any three side lengths to form a triangle of non-zero area, we return 0.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>3 &lt;= nums.length &lt;= 10<sup>4</sup></code></li>
	<li><code>1 &lt;= nums[i] &lt;= 10<sup>6</sup></code></li>
</ul>
Greedy; Array; Math; Sorting
function largestPerimeter(nums: number[]): number {
    const n = nums.length;
    nums.sort((a, b) => b - a);
    for (let i = 2; i < n; i++) {
        const [a, b, c] = [nums[i - 2], nums[i - 1], nums[i]];
        if (a < b + c) {
            return a + b + c;
        }
    }
    return 0;
}
