/*

Hashing

Time complexity

================

Ordered Map : Best case, worst case and average case TC is O(log n)

Unordered Map : Best case, average case TC is O(1) and worst case is O(n)

Implementation

===============

*/

import java.io.*;

import java.util.*;

public class StringHashing{

//Logic if all character in given string are lower case

public static int checkCharacterOccurranceInGivenString(String s, char key){

//hash array

int[] hash = new int[26];

Arrays.fill(hash,0);

//creation of hash array

for(char ch : s.toCharArray()){

hash[ch - 'a']++;

}

return hash[key-'a'];

}

//Logic if all character in given string are either lower case or upper case

public static int checkCharacterOccurranceInGivenStringSplCase(String s, char key){

//hash array

int[] hash = new int[256];

Arrays.fill(hash,0);

//creation of hash array

for(char ch : s.toCharArray()){

hash[ch]++;

}

return hash[key];

}

public static void main(String[] args){

String s = "samuell";

char key = 'l';

System.out.println("The occurrence of letter "+ key +" is :" +checkCharacterOccurranceInGivenString(s,key));

s = " SaHRRUreLL";

key = 'r';

System.out.println("The occurrence of letter "+ key +" is :" +checkCharacterOccurranceInGivenStringSplCase(s,key));

}

}

/* o/p:-

The occurrence of letter l is :2

The occurrence of letter r is :1

*/