Given two strings string1 and string2, find the smallest substring in string1 containing all characters of string2 efficiently.
Input : string = "this is a test string" pattern = "tist" Output : Minimum window is "t stri" Explanation: "t stri" contains all the characters of pattern. Input : string = "geeksforgeeks" pattern = "ork" Output : Minimum window is "ksfor"
Method 1 ( Brute force solution )
1- Generate all substrings of string1 (“this is a test string”)
2- For each substring, check whether the substring contains all characters of string2 (“tist”)
3- Finally, print the smallest substring containing all characters of string2.
Method 2 ( Efficient Solution )
1- First check if length of string is less than the length of given pattern, if yes then "no such window can exist ". 2- Store the occurrence of characters of given pattern in a hash_pat. 3- Start matching the characters of pattern with the characters of string i.e. increment count if a character matches 4- Check if (count == length of pattern ) this means a window is found 5- If such window found, try to minimize it by removing extra characters from beginning of current window. 6- Update min_length. 7- Print the minimum length window.
Diagram to explain above algorithm:
Below is program to implement above algorithm
Smallest window is : t stri
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