JavaProgramming/Recursion/PrintKeypadCombination.java at main · PrityKumari14/JavaProgramming · GitHub

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/*Print keypad combination

( 0 -> .;

1 -> abc

2 -> def

3 -> ghi

4 -> jkl

5 -> mno

6 -> pqrs

7 -> tu

8 -> vwx

9 -> yz

)*/

// time complexity = O(4^n)

package Recursion;

public class PrintKeypadCombination {

public static String[] keypad = {".", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tu","vwx", "yz"};

public static void printComb(String str, int idx, String combination){

if(idx == str.length()){

System.out.println(combination);

return;

}

char currChar = str.charAt(idx);

String mapping = keypad[currChar - '0'];

for(int i=0; i<mapping.length(); i++){

printComb(str, idx+1, combination+mapping.charAt(i));

}

public static void main(String[] args) {

String str = "61";

printComb(str, 0,"");

}

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