Get Max to the left of an array, this can also be used to get max to the right of an array

MaxFromAnIndex.py

nums = [0,1,0,2,1,0,1,3,2,1,2,1]
n = len(nums)

# Function to get max to the left
# of each index of an array
def maxToLeft(arr):
    
    # Nothing left for first index
    maxLeft = [-1]
    
    # Find max to the left of each
    # index
    l = arr[0]
    for a in arr[1:]:
        l = max(l, a)
        maxLeft.append(l)
        
    # return     
    return maxLeft # ~maxToLeft()

max_left = maxToLeft(nums)
max_right = maxToLeft(nums[::-1])
max_right = max_right[::-1]

print(nums)
print(max_left)
print(max_right)

"""
Original:  [0,  1,  0,  2,  1,  0,  1,  3,  2,  1,  2,  1]
Max Left:  [-1, 1,  1,  2,  2,  2,  2,  3,  3,  3,  3,  3]
Max Right: [3,  3,  3,  3,  3,  3,  3,  3,  2,  2,  2, -1]
"""