------
## 最终结论
```python
def is_Monotonic(array):
    increasing = True
    decreasing = True
    
    for i in range(1, len(array)):
        if array[i] < array[i - 1]:
            increasing = False
        if array[i] > array[i - 1]:
            decreasing = False
            
    return increasing or decreasing

# Test cases
assert is_Monotonic([6, 5, 4, 4]) == True
assert is_Monotonic([1, 2, 2, 3]) == True
assert is_Monotonic([1, 3, 2]) == False
```