How to check all the integers in the list are continuous?

I am trying to write a program which will print "YES" if all the numbers in the list are continuous and should return "NO" if the numbers are not continuous. By continuous I mean every number in the list should be greater than one from the previous element.

For example:

It should print "YES" for inputs: [3, 4, 5], [7, 8, 9], [1, 2, 3], [0, 1, 2, 3, 4, 5].. etc
It should print "NO" for inputs: [9, 1, 0], [3, 2, 4], [5, 5], [9, 8, 2, 3, 7].. etc

I used enumerate for this purpose.

Here's my code:

    inp=[1,2,3,4,5]
    flag=0
    for index,e in enumerate(inp): 
        if index!=len(inp)-1:    
            if inp[index+1]==inp[index]+1:
                flag=1
    if flag==1:
        print ("YES")
    else:
        print ("NO")

The code works fine but i find it redundant.
Is there a better way to do it using enumerate or without using enumerate?

Solution

You don't need enumerate in order to check the elements of your lists are continuous. You can simply achieve it via creating a function using zip and all as:

def check_continuity(my_list):
    return all(a+1==b for a, b in zip(my_list, my_list[1:]))

Same result can be achieved by any with zip as (similar to all but with not and != for comparision):

def check_continuity(my_list):
    return not any(a+1!=b for a, b in zip(my_list, my_list[1:]))

Above functions will return True/False depending upon whether your list is continuous or not.

Sample run:

# Continuous Lists
>>> check_continuity([3, 4, 5])
True
>>> check_continuity([7, 8, 9])
True
>>> check_continuity([1, 2, 3])
True

# Non Continuous Lists
>>> check_continuity([9, 1, 0])
False
>>> check_continuity([3, 2, 4])
False
>>> check_continuity([5, 5])
False

In order to print "YES"/"NO", you may make a simple if..elsecheck outside the function call as:

>>> "YES" if check_continuity([1, 2, 3]) else "NO"
'YES'

# OR update the return statement in your function to
#    return "NO" if any(a+1!=b for a, b in zip(my_list, my_list[1:])) else "YES"