Maximum of Absolute Value Expression
<p>Given two arrays of integers with equal lengths, return the maximum value of:</p>

<p><code>|arr1[i] - arr1[j]| + |arr2[i] - arr2[j]| + |i - j|</code></p>

<p>where the maximum is taken over all <code>0 &lt;= i, j &lt; arr1.length</code>.</p>

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

<pre>
<strong>Input:</strong> arr1 = [1,2,3,4], arr2 = [-1,4,5,6]
<strong>Output:</strong> 13
</pre>

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

<pre>
<strong>Input:</strong> arr1 = [1,-2,-5,0,10], arr2 = [0,-2,-1,-7,-4]
<strong>Output:</strong> 20
</pre>

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

<ul>
	<li><code>2 &lt;= arr1.length == arr2.length &lt;= 40000</code></li>
	<li><code>-10^6 &lt;= arr1[i], arr2[i] &lt;= 10^6</code></li>
</ul>
Array; Math
func maxAbsValExpr(arr1 []int, arr2 []int) int {
	dirs := [5]int{1, -1, -1, 1, 1}
	const inf = 1 << 30
	ans := -inf
	for k := 0; k < 4; k++ {
		a, b := dirs[k], dirs[k+1]
		mx, mi := -inf, inf
		for i, x := range arr1 {
			y := arr2[i]
			mx = max(mx, a*x+b*y+i)
			mi = min(mi, a*x+b*y+i)
			ans = max(ans, mx-mi)
		}
	}
	return ans
}