message: Update maximum-of-absolute-value-expression.cpp
diff: class Solution {
  public:
  int maxAbsValExpr(vector<int>& arr1, vector<int>& arr2) {
  + // 1. max(|arr1[i]-arr1[j]| + |arr2[i]-arr2[j]| + |i-j| for i > j)
  + // = max(|arr1[i]-arr1[j]| + |arr2[i]-arr2[j]| + |i-j| for j > i)
  + // 2. for i > j:
  + // (|arr1[i]-arr1[j]| + |arr2[i]-arr2[j]| + |i-j|)
  + // >= c1*(arr1[i]-arr1[j]) + c2*(arr2[i]-arr2[j]) + i-j for c1 in (1, -1), c2 in (1, -1)
  + // = (c1*arr1[i]+c2*arr2[i]+i) - (c1*arr1[j]+c2*arr2[j]+j) for c1 in (1, -1), c2 in (1, -1)
  + // 1 + 2 => max(|arr1[i]-arr1[j]| + |arr2[i]-arr2[j]| + |i-j| for i != j)
  + // = max((c1*arr1[i]+c2*arr2[i]+i) - (c1*arr1[j]+c2*arr2[j]+j)
  + // for c1 in (1, -1), c2 in (1, -1) for i > j)
  int result = 0;
  for (const auto& c1 : {1, -1}) {
  for (const auto& c2 : {1, -1}) {
  