# Python program to find N-sized substrings with K distinct characters

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When it is required to find N sized substrings which have K distinct characters, a method is defined that takes three parameters and uses ‘if’ condition to return the required string.

## Example

Below is a demonstration of the same

def generate_my_string(string_size, substring_size, distinct_chars):

my_string = ""
count_1 = 0
count_2 = 0

for i in range (string_size):
count_1 += 1
count_2 += 1

if (count_1 <= substring_size):
if (count_2 <= distinct_chars):
my_string = my_string + chr(96 + count_1)

else:
my_string = my_string + 'a'

else:
count_1 = 1
count_2 = 1
my_string = my_string + 'a'

return my_string

my_string_size = 8
my_substring_size = 6
K_distinct_chars = 4

print("The string size is :")
print(my_string_size)

print("The substring size is :")

print(my_substring_size)

print("The distinct characters count is :")
print(K_distinct_chars)

print("The resultant string is :")
print(generate_my_string(my_string_size, my_substring_size, K_distinct_chars))

## Output

The string size is :
8
The substring size is :
6
The distinct characters count is :
4
The resultant string is :
abcdaaab

## Explanation

• A method named ‘generate_my_string’ is defined that takes the string size, the substring size and the distinct characters as parameters.

• An empty string is defined.

• Two integer values are initialized to 0.

• The string size is iterated over, and the two integer values are incremented.

• If the first integer value is less than or equal to the size of the substring, the character is converted into a different character.

• Otherwise, it is concatenated with the letter ‘a’.

• Otherwise, the two integer variables are assigned to 1.

• This string is returned as output.

• Outside the method, the string size, the substring size and the number of distinct characters are defined.

• These values are displayed on the console.

• The method is called by passing these parameters.

• The output is displayed on the console.

Updated on 20-Sep-2021 08:36:41