message: Update minimum-operations-to-make-array-equal.cpp
diff: class Solution {
  public:
  int minOperations(int n) {
  - // total = (2i+1 for i in xrange(n)) = n^2
  - // left_half_total = (2i+1 for i in xrange(n//2)) = (n//2)^2
  + // total = sum(2i+1 for i in xrange(n)) = n^2
  + // left_half_total = sum(2i+1 for i in xrange(n//2)) = (n//2)^2
  // result = (n//2) * (total//n) - left_half_total = (n//2)*(n-n//2) = (n//2)*((n+1)//2)
  return (n / 2) * ((n + 1) / 2);
  }
  