On one of my previous courseworks, I was faced with the following problem, which I think is unrealistic when using a direct / straightforward approach that usually algorithms have by leveraging certain data structures like dictionaries, etc.

> Design an O(log n) algorithm whose input is a sorted list A. The algorithm
should return true if A contains at least 4 distinct elements. Otherwise
the algorithm should return false.

My lecturer came up with the following solution:

```python
def ThreeDiff(A):
 if A[0]==A[len(A)-1]:
  return -1

 minind=0
 maxind=len(A)-1

 while maxind-mind>1:
  midind=int((minind+maxind)/2)
  if A[midind]>A[minind] and A[midind]<A[maxind]:
   return midind
  if A[midind]==A[minind]:
   minind=midind
  else
   maxind=midind
return -1

def FourDiff(A):
  midind=ThreeDiff(A)
  if midind==-1:
   return false
  return ThreeDiff(A[0:midind+1])!=- 1 or ThreeDiff(A[midind:len(A)]) != -1
```

Is there a cleaner or better way to solve this problem?