Length of the smallest sub-string consisting of maximum distinct characters
Given a string of length N, find the length of the smallest sub-string consisting of maximum distinct characters. Note : Our output can have same character.
Examples:
Input : "AABBBCBB" Output : 5 Input : "AABBBCBBAC" Output : 3 Explanation : Sub-string -> "BAC" Input : "GEEKSGEEKSFOR" Output : 8 Explanation : Sub-string -> "GEEKSFOR"
Method 1 (Brute Force)
We can consider all sub-strings one by one and check for each sub-string both conditions together
1. sub-string’s distinct characters is equal to maximum distinct characters
2. sub-sting’s length should be minimum .
Time Complexity : O(n^3)
C++
/* C++ program to find the length of the smallest substring consisting of maximum distinct characters */#include <bits/stdc++.h> using namespace std; #define NO_OF_CHARS 256 // Find maximum distinct characters in any string int max_distinct_char(string str, int n){ // Initialize all character's count with 0 int count[NO_OF_CHARS] = {0}; // Increase the count in array if a character // is found for (int i = 0; i < n; i++) count[str[i]]++; int max_distinct = 0; for (int i = 0; i < NO_OF_CHARS; i++) if (count[i] != 0) max_distinct++; return max_distinct; } int smallesteSubstr_maxDistictChar(string str){ int n = str.size(); // size of given string // Find maximum distinct characters in any string int max_distinct = max_distinct_char(str, n); int minl = n; // result // Brute force approach to find all substrings for (int i=0 ;i<n ;i++){ for (int j=0; j<n; j++){ string subs = str.substr(i,j); int subs_lenght = subs.size(); int sub_distinct_char = max_distinct_char(subs, subs_lenght); // We have to check here both conditions together // 1. substring's distinct characters is equal // to maximum distinct characters // 2. substing's length should be minimum if (subs_lenght < minl && max_distinct == sub_distinct_char){ minl = subs_lenght; } } } return minl; } /* Driver program to test above function */int main() { // Input String string str = "AABBBCBB"; int len = smallesteSubstr_maxDistictChar(str); cout << " The length of the smallest substring" " consisting of maximum distinct " "characters : " << len; return 0; } |
Java
/* Java program to find the length of the smallest substring consisting of maximum distinct characters */class GFG { final static int NO_OF_CHARS = 256; // Find maximum distinct characters in any string static int max_distinct_char(String str, int n) { // Initialize all character's count with 0 int count[] = new int[NO_OF_CHARS]; // Increase the count in array if a character // is found for (int i = 0; i < n; i++) { count[str.charAt(i)]++; } int max_distinct = 0; for (int i = 0; i < NO_OF_CHARS; i++) { if (count[i] != 0) { max_distinct++; } } return max_distinct; } static int smallesteSubstr_maxDistictChar(String str) { int n = str.length(); // size of given string // Find maximum distinct characters in any string int max_distinct = max_distinct_char(str, n); int minl = n; // result // Brute force approach to find all substrings for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { String subs = null; if(i<j) subs = str.substring(i, j); else subs = str.substring(j, i); int subs_lenght = subs.length(); int sub_distinct_char = max_distinct_char(subs, subs_lenght); // We have to check here both conditions together // 1. substring's distinct characters is equal // to maximum distinct characters // 2. substing's length should be minimum if (subs_lenght < minl && max_distinct == sub_distinct_char) { minl = subs_lenght; } } } return minl; } /* Driver program to test above function */ static public void main(String[] args) { // Input String String str = "AABBBCBB"; int len = smallesteSubstr_maxDistictChar(str); System.out.println(" The length of the smallest substring" + " consisting of maximum distinct " + "characters : "+len); } } // This code is contributed by 29AjayKumar |
Python 3
# Python 3 program to find the length # of the smallest substring consisting # of maximum distinct characters NO_OF_CHARS = 256 # Find maximum distinct characters # in any string def max_distinct_char(str, n): # Initialize all character's # count with 0 count = [0] * NO_OF_CHARS # Increase the count in array # if a character is found for i in range(n): count[ord(str[i])] += 1 max_distinct = 0 for i in range(NO_OF_CHARS): if (count[i] != 0): max_distinct += 1 return max_distinct def smallesteSubstr_maxDistictChar(str): n = len(str) # size of given string # Find maximum distinct characters # in any string max_distinct = max_distinct_char(str, n) minl = n # result # Brute force approach to # find all substrings for i in range(n): for j in range(n): subs = str[i:j] subs_lenght = len(subs) sub_distinct_char = max_distinct_char(subs, subs_lenght) # We have to check here both conditions together # 1. substring's distinct characters is equal # to maximum distinct characters # 2. substing's length should be minimum if (subs_lenght < minl and max_distinct == sub_distinct_char): minl = subs_lenght return minl # Driver Code if __name__ == "__main__": # Input String str = "AABBBCBB" l = smallesteSubstr_maxDistictChar(str); print( "The length of the smallest substring", "consisting of maximum distinct", "characters :", l) # This code is contributed by ChitraNayal |
C#
/* C# program to find the length of the smallest substring consisting of maximum distinct characters */using System; class GFG { static int NO_OF_CHARS = 256; // Find maximum distinct characters in any string static int max_distinct_char(String str, int n) { // Initialize all character's count with 0 int []count = new int[NO_OF_CHARS]; // Increase the count in array if a character // is found for (int i = 0; i < n; i++) { count[str[i]]++; } int max_distinct = 0; for (int i = 0; i < NO_OF_CHARS; i++) { if (count[i] != 0) { max_distinct++; } } return max_distinct; } static int smallesteSubstr_maxDistictChar(String str) { int n = str.Length; // size of given string // Find maximum distinct characters in any string int max_distinct = max_distinct_char(str, n); int minl = n; // result // Brute force approach to find all substrings for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { String subs = null; if(i < j) subs = str.Substring(i, str.Length-j); else subs = str.Substring(j, str.Length-i); int subs_lenght = subs.Length; int sub_distinct_char = max_distinct_char(subs, subs_lenght); // We have to check here both conditions together // 1. substring's distinct characters is equal // to maximum distinct characters // 2. substing's length should be minimum if (subs_lenght < minl && max_distinct == sub_distinct_char) { minl = subs_lenght; } } } return minl; } /* Driver program to test above function */ static public void Main(String[] args) { // Input String String str = "AABBBCBB"; int len = smallesteSubstr_maxDistictChar(str); Console.WriteLine(" The length of the smallest substring" + " consisting of maximum distinct " + "characters : "+len); } } // This code contributed by Rajput-Ji |
PHP
<?php /* PHP program to find the length of the smallest substring consisting of maximum distinct characters */ $NO_OF_CHARS=256; // Find maximum distinct characters in any string function max_distinct_char($str, $n) { global $NO_OF_CHARS; // Initialize all character's count with 0 $count = array_fill(0, $NO_OF_CHARS, 0); // Increase the count in array if a character // is found for ($i = 0; $i < $n; $i++) $count[ord($str[$i])]++; $max_distinct = 0; for ($i = 0; $i < $NO_OF_CHARS; $i++) if ($count[$i] != 0) $max_distinct++; return $max_distinct; } function smallesteSubstr_maxDistictChar($str) { $n = strlen($str); // size of given string // Find maximum distinct characters in any string $max_distinct = max_distinct_char($str, $n); $minl = $n; // result // Brute force approach to find all substrings for ($i = 0 ; $i < $n ; $i++) { for ($j = 0; $j < $n; $j++) { $subs = substr($str, $i, $j); $subs_lenght = strlen($subs); $sub_distinct_char = max_distinct_char($subs, $subs_lenght); // We have to check here both conditions together // 1. substring's distinct characters is equal // to maximum distinct characters // 2. substing's length should be minimum if ($subs_lenght < $minl && $max_distinct == $sub_distinct_char) { $minl = $subs_lenght; } } } return $minl; } /* Driver code */ // Input String $str = "AABBBCBB"; $len = smallesteSubstr_maxDistictChar($str); echo " The length of the smallest substring" ." consisting of maximum distinct characters : ".$len; // This coe is contributed by mits ?> |
Output:
The length of the smallest substring consisting of maximum distinct characters : 5
Method 2 (Efficient)
- Count all distinct characters in given string.
- Maintain a window of characters. Whenever the window contains all characters of given string, we shrink the window from left side to remove extra characters and then compare its length with smallest window fount so far.
Please refer Smallest window that contains all characters of string itself for implementation and more details.
Asked In : DailyHunt
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