Java 30 Days of Code - Day 6 - Strings

In this article, we will learn about Strings output question which is often asked in the interview problems. 

Java 30 Days of Code - Day 6 - Strings

Problem statement -

Take an input from the user in Integer. Based upon the input parameter, accept the String values and print even/ odd characters. For an example

Input - 2

            Hacker

            Rank

Output 

    Hce akr

    Rn ak

Program -

Scanner scan = new Scanner(System.in);
    int T = scan.nextInt();
    String string[] = new String[T];
    for(int i = 0; i<T; i++){
        string[i] = scan.next();
    }
    for(int temp = 0; temp<T; temp++){

        for(int j = 0; j<string[temp].length(); j = j+2)
        {
            System.out.print(string[temp].charAt(j));
        }
        System.out.print(" ");

        for(int j = 1; j<string[temp].length(); j = j+2){
            System.out.print(string[temp].charAt(j));
        }

        System.out.println();

    }
    scan.close();
}

Explanation -

• Firstly, we are taking an input for the number of test cases using variable T.
• Now we are creating an array called string[] add adding a loop to capture the strings in string array.
• Afterwards, we are running nested loop, outer loop is for T, inner loop for J for traversing from 0 to length of the array.
• Second loop starts from 1 to length of the array. 
• Both the statements have a line break at the end of the last loop.

2nd program -

 

Input String - "AAAABBCCCDDDDEEEG"

Output String - "A4B2C3D4E3G1"

Program -

public static void main(String[] args) {

String s ="AAAABBCCCDDDDEEEG";

ArrayList<Character> list = new ArrayList<>();

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

{

int count=1;

if(!list.contains(s.charAt(i)))

{

list.add(s.charAt(i));

for(int j=i+1;j<s.length();j++)

{

if(s.charAt(i)==s.charAt(j))

{

count++;

}

}

System.out.print(s.charAt(i)+""+count);

}

}

}

Explanation -

• First we create an ArrayList which accepts Character return type.
• Will iterate with first loop until the string's length
• Declare count variable with value 1.
• If array list contains s.charAt(i)
• then add it to the list
• Declare another loop where j = i +1(next character)
• If char(i) == char(j)
• count++
• End J loop and print s.charAt(i) with count

Problem statement 3-

Example Input String - weelccoommee hhoommeee

Output String - welcome home

Objective is to remove consecutive characters from the string.

Solution -

We will post this solution soon

Problem statement 4 -

Example Input String - aabbbccdda

Output string -

aa-2
bbb-3
cc-2
d-1

a-1

Solution -

import java.util.*;

class Main {

public static void main([] args) {

String s = "aabbbccda";

char[] c = s.toCharArray();

int length = 0;

for(char d: c){

length++;

}

HashMap<Character, Integer> hp = new HashMap<Character, Integer>();

for(int i=0;i<length;i++)

{

if(hp.containsKey(c[i])){

hp.put(c[i],hp.get(c[i])+1);

}

else {

hp.put(c[i],1);

}

}

System.out.println(hp);

}

}

Explanation -

• First we will split characters using char Array.
• Declare a variable with length = 0
• Capture the entire length of characters using for each loop.
• Declare HashMap with character and Integer data types.
• For loop from 0 to length
• If hashmap contains Key c[i]
• put c[i], hp.get(c[i] + 1)
• else put c[i],1
• System out hp