def increment_large_number(digits):
    n = len(digits)
    
   
    for i in range(n - 1, -1, -1):
        if digits[i] < 9:
            digits[i] += 1  
            return digits
        digits[i] = 0  
    
   
    return [1] + digits 

# Test cases
print(increment_large_number([1, 2, 3]))  
print(increment_large_number([4, 3, 2, 1]))  
print(increment_large_number([9])) 
print(increment_large_number([1, 0, 0]))  
print(increment_large_number([9, 9, 9]))