Given two strings string1 and string2, the task is to 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 )
- First check if the length of string is less than the length of the given pattern, if yes then “no such window can exist “.
- Store the occurrence of characters of the given pattern in a hash_pat.
- Start matching the characters of pattern with the characters of string i.e. increment count if a character matches.
- Check if (count == length of pattern ) this means a window is found.
- If such window found, try to minimize it by removing extra characters from the beginning of the current window.
- Update min_length.
- Print the minimum length window.
Diagram to explain the above algorithm:
Below is the program to implement the above algorithm:
Smallest window is : t stri
This article is contributed by Sahil Chhabra. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to email@example.com. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
- Smallest window that contains all characters of string itself
- Python | Get the smallest window in a string containing all characters of given pattern
- Lexicographically smallest string formed by appending a character from the first K characters of a given string
- Lexicographically smallest string formed by appending a character from first K characters of a string | Set 2
- Program to find the largest and smallest ASCII valued characters in a string
- Swap all occurrences of two characters to get lexicographically smallest string
- Length of the smallest sub-string consisting of maximum distinct characters
- Minimal moves to form a string by adding characters or appending string itself
- Create a new string by alternately combining the characters of two halves of the string in reverse
- Minimum deletions from string to reduce it to string with at most 2 unique characters
- Find the character made by adding all the characters of the given string
- Find the longest substring with k unique characters in a given string
- Find the player who rearranges the characters to get a palindrome string first
- Python Dictionary to find mirror characters in a string
- Program to find Smallest and Largest Word in a String