Given a string of lowercase alphabets, the task is to find indexes of a substring with given power. Assume power of a to be 1, b to be 2, c to be 3 and so on. Here the power of a substring means the sum of the powers of all the characters in that particular substring.
Input: str = “geeksforgeeks” power = 36
Output: Substring from index 3 to 5 has power 36
Explanation: k = 11, s = 19, f = 6 i.e. k + s + e = 36.
Input: str = “aditya” power = 2
Output: No substring with given power exists.
1. Calculate powers of all substrings using nested for loops.
2. If the power of any substring equals the given power then print the indexes of the substring.
3. If no such substring exists then print “No substring with given power exists”.
Time Complexity: O (n ^ 2).
Efficient Approach: Use map to store the powers.
1. For each element check if curr_power – power exists in the map or not.
2. If it exists in the map it means that we have a substring present with given power, else we insert curr_power into the map and proceed to the next character.
3. If all characters of the string are processed and we didn’t find any substring with given power, then substring doesn’t exist.
Substring from index 3 to 5 has power 36
Time Complexity: O (n)
- Given a string, find its first non-repeating character
- Find the smallest window in a string containing all characters of another string
- Length of the longest substring without repeating characters
- Longest Non-palindromic substring
- Given a number, find the next smallest palindrome
- Longest Palindromic Substring | Set 1
- Longest Palindromic Substring | Set 2
- Longest Common Substring | DP-29
- Find if a string is interleaved of two other strings | DP-33
- Find the first non-repeating character from a stream of characters
- Find Excel column name from a given column number
- Given a sorted dictionary of an alien language, find order of characters
- Find if an array of strings can be chained to form a circle | Set 1
- Given two strings, find if first string is a subsequence of second
- Manacher's Algorithm - Linear Time Longest Palindromic Substring - Part 1
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to firstname.lastname@example.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.