如何在Java中打印字符串数组的偶数和奇数位置字符？

Question

Question

Given a string S of length N, that is indexed from 0 to N-1, print it's even indexed and odd indexed characters as 2 space separated strings on a single line. Assume input starts at index position 0(which is considered even)

Input

The first line contains an integer, T (the number of test cases). Each line i of the T subsequent lines contain a String, S.

Output

For each string S, print it's even-indexed characters, followed by space, followed by odd-indexed characters.

Sample Input

2

Hacker

Rank

Sample Output

Hce akr

Rn ak

The Code I Wrote

public static void main(String[] args)
{
    Scanner scan    =   new Scanner(System.in);
    int T   =   scan.nextInt();
    scan.nextLine();

    for(int i=0 ; i<T ; i++)
    {
        String  myString    =   scan.nextLine();

        int evn =   0,
            odd =   0,
            len =   myString.length();

        char    strE[]  =   new char[50],
                strO[]  =   new char[50];

        for(int j=0 ; j<len ; j++)
        {
            if(j%2 == 0)
            {
                strE[evn]   =   myString.charAt(j);
                evn++;
            }
            if(j%2 == 1)
            {
                strO[odd]   =   myString.charAt(j);
                odd++;
            }
        }
        System.out.print(strE);
        System.out.print(" ");
        System.out.println(strO);
    }
}

My Output

Hce akr

Rn ak

The Problem

As you can see, my program successfully meets the test case, and other test cases (using custom input) but every time the HackerRank compiler tells me that my program did not meet the test case.

Clearly, my program is producing the required output but every time the HackerRank compiler tells me that I got the solution wrong.

Could anyone please tell me where I am making a mistake?

Further Modifications

I then decided to change the last 3 lines of print statements into one statement as follows:

System.out.println(strE + " " + strO);

However, this time the program did not produce the desired output and rather printed some garbage values as follows:

[C@5c3f3b9b [C@3b626c6d

[C@3abc8690 [C@2f267610

My Doubts

1. In the first case, when I was printing the two strings separately using 2 print statements, I was getting a correct output everytime but the HackerRank compiler rejected it. Why?

2. In the second case, when I modified the program by using one print statement instead of 3 to get the desired result, the program gave a completely different output and rather printed garbage values! Why?

Here is a link to the HackerRank problem for more info: hackerrank.com/challenges/30-review-loop

All help and guidance is greatly appreciated and thanks a lot in advance!

Answer 1

Try to submit this:

Scanner scan = new Scanner(System.in);
int T = scan.nextInt();
scan.nextLine();
for (int i = 0; i < T; i++) {
    String myString = scan.nextLine();
    String even = "";
    String odd = "";
    for (int j = 0; j < myString.length(); j++) {
        if (j % 2 == 0) {
            even += myString.charAt(j);
        } else {
            odd += myString.charAt(j);
        }
    }

    System.out.println(even + " " + odd);
}

i get the right output and it should meet all the requirements. i think your code fails because its not a real string you print in the end and you have empty spots in your arrays

Answer 2

    Scanner scanner = new Scanner(System.in);
    System.out.println("Enter the no.of test-cases:");
    int t = scanner.nextInt();
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    System.out.println("Enter the String(s)");
    for (int i = 0; i < t; i++) {

        String myString = br.readLine();
        String even = "";
        String odd = "";
        for (int j = 0; j < myString.length(); j++) {
            if (j % 2 == 0) {
                even += myString.charAt(j);
            } else {
                odd += myString.charAt(j);
            }
        }
        System.out.println(even);
        System.out.println(odd);
    }
    scanner.close();

Answer 3

I can solve your the second question: ---> System.out.print(strE);-->At the bottom, the method is called( public void print(char s[]));

-->System.out.println(strE + " " + strO);-->At the bottom, the method is called (public void println(String x) )

Answer 4

For your first answer I am unable to answer you as I have no idea about how the compiler works, but I can answer your second question.

The reason why System.out.print(strE); System.out.print(" "); System.out.println(strO); System.out.print(strE); System.out.print(" "); System.out.println(strO); works is because System.out.print(char[]) and System.out.println(char[]) automatically turn the char arrays into a readable string before printing it.

However, in the second case System.out.println(strE + " " + strO); , what you are doing is directly turning the char array into strings, which just prints the class and the hash code of the array object because the toString() method is not overriden in the array class. What you want to do is System.out.println(new String(strE) + " " + new String(strO)); . It will give you the result you want.

Answer 5

int T = scan.nextInt();

This reads quantity of test cases, which we're going to process.

String string[] = new String[T];
for(int i = 0; i<T; i++){
  string[i] = scan.next();

} Next we're creating an array named "string" (BTW, this a bad name for variables/objects) which has size T and in the for loop reading test cases from the input T times and saving them in the array.

for(int temp = 0; temp<T; temp++){

Now, for each of test cases we do the following...

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

We create a local variable j, which is visible only in this for loop. j holds index of the string (=string[temp]), which we're processing. So, we're printing a character on position j (by using standard method "charAt" of String class, which returns character of given index of the string) and then increasing it by 2. So, this code will print every even character. For string "example", it will print "eape" (j=0, j=2, j=4, j=6).

System.out.print(" ");

Separating sequences with a space.

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

System.out.println();

We're doing the same (creating index j, running though all characters of the string), but starting from "1", so it will print all odd characters of the string. For string "example", it will give you "xml" (j=1, j=3, j=5). and After this, it will end the string. I hope, it will help you to understand. :)

Answer 6

import java.io.*;
import java.util.*;

public class Solution {

 private static void f(String s) {
 // TODO Auto-generated method stub
  char c[]=s.toCharArray();
  int i,j;
  for (i = 0; i <c.length;i++){ 
      System.out.print(c[i]);
      i+=1;
  }
  System.out.print(" ");
  for (j = 1; j<c.length;j++){
     System.out.print(c[j]);
     j+=1;    
  }
 }
 public static void main(String[] args){
    // TODO Auto-generated method stub
    Scanner sc=new Scanner(System.in);
    int s=sc.nextInt();
    while(hasNext()){
    //for loop for multiple strings as per the input
        for(int m=0;m<= s;m++){    
          String s1=sc.next();
          f(s1); 
          System.out.println();
        }
     }
   }
}

Answer 7

I've solved this question in 2 ways & both are producing correct output.

Have a look & let me know if you've any problem.

1. Instead of using char array, you can use String

    //char[] even = new char[10000]; String even = "";

Let's look at the code

private static Scanner scanner = new Scanner(System.in); 

public static void main(String[] args) {

        String s = scanner.next();

        char[] array = s.toCharArray();

        int count=0;            
        //char[] even = new char[10000];
        //char[] odd = new char[10000];
        String even = "";
        String odd = "";
        for(char ch : array){

            if(count%2 == 0){
                even = even + ch;
            }else{
                odd = odd + ch;
            }
            count++;
        }
        count = 0;

        System.out.println(even + " " + odd);
}

Output:

  hacker
  hce akr

2. No need of extra char[] or String to store even & odd position characters, we can directly print them using appropriate condition.

    private static Scanner scanner = new Scanner(System.in); public static void main(String[] args){ String s = scanner.next(); char[] array = s.toCharArray(); int count=0; for(char ch : array){ if(count%2 == 0){ System.out.print(ch); } count++; } count = 0; System.out.print(" "); for(char ch : array){ if(count%2 != 0){ System.out.print(ch); } count++; } count = 0; }

Output:

  hacker
  hce akr

Answer 8

Try this:

public static void main(String[] args) {
    System.out.println("Enter string to check:");
    Scanner scan = new Scanner(System.in);
    String T = scan.nextLine();
    String even = "";
    String odd = "";
    for (int j = 0; j < T.length(); j++) {
        if (j % 2 == 0) { //check the position of the alphabet by dividing it by 0
            even += T.charAt(j);
        } else {
            odd += T.charAt(j);
        }
    }
    System.out.println(even + " " + odd);

    scan.close();
}

Answer 9

** JavaScript version **

function processData(input) {
   for (let i = 1; i < input.length; i++) {
     printOutput(input[i]);
   }
}

function printOutput(input) {
  var result = [];
  input.length % 2 == 0 ? result[input.length / 2] = ' ': result[Math.ceil(input.length / 2)] = ' ';
  for (let i = 0; i < input.length; i++) {
    if (i % 2 == 0) {
        result[i / 2] = input[i];
    }
    else {
        result[Math.ceil(input.length / 2) + Math.ceil(i / 2)] = input[i];
    }
}
console.log(result.join(''));
}

process.stdin.on("end", function () {
processData(_input.split('\n'));

});

Answer 10

import java.io. * ;
import java.util. * ;

public class Solution {
String myString;
public Solution(String myString) {
    this.myString = myString;
    int len = myString.length();
    for (int j = 0; j < len; j++) {
        if (j % 2 == 0) {
            System.out.print(myString.charAt(j));
        }
    }
    System.out.print(" ");
    for (int j = 0; j < len; j++) {

        if (j % 2 == 1) {
            System.out.print(myString.charAt(j));
        }
    }
}
public static void main(String[] args) {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
    Scanner sc = new Scanner(System. in );
    int T = sc.nextInt();
    for (int i = 0; i < T; i++) {
        String word = sc.next();
        Solution sol = new Solution(word);
        System.out.println();
    }
    sc.close();
}

}

Answer 11

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
       Scanner s = new Scanner(System.in);
        int T;
        T = s.nextInt();
        String[] str = new String[T];
        int i;
        for(i=0;i<T;i++) {
            str[i] = s.next();
        }    
        for(i=0;i<T;i++) {
            char[] even = new char[5000];
            char[] odd = new char[5000];
            int ev =0,od=0;
            for(int j= 0;j< str[i].length();j++) {
                if(j%2== 0) {
                    even[ev] = str[i].charAt(j);
                    ev++;
                }else {
                    odd[od] = str[i].charAt(j);
                    od++;
                }
            }
            String strEven = new String(even);
            String strOdd = new String(odd);
           System.out.print(strEven.trim());
           System.out.print(" ");
           System.out.println(strOdd.trim());

        }
        s.close();
    }
}

I am sure that this will work You've forgotten to convert it to a string and also increase the size of the character array

Answer 12

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        Scanner scan= new Scanner(System.in);
        int n= scan.nextInt();
        for(int i=0;i<n;i++){
            String s= scan.next();
            int len= s.length();
            StringBuffer str_e= new StringBuffer();
            StringBuffer str_o= new StringBuffer();
            for(int j=0;j<len;j++){
                if(j%2==0)
                    str_e= str_e.append(s.charAt(j));
                if(j%2==1)
                    str_o= str_o.append(s.charAt(j));
            }
            System.out.println(str_e+" "+str_o);
        }
    }
}

Answer 13

Try this:

import java.io.*;
import java.util.*;

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner pp=new Scanner(System.in);
        int n=pp.nextInt();

        for(int i=0; i<n; i++)
        {
            String ip=pp.next();
            String re1="",
                    re2="";
            for(int j=0; j<ip.length(); j++)
            {
                if(j%2 == 0)
                {
                    re1+= ip.charAt(j);
                }
                if(j%2 == 1)
                {
                    re2+= ip.charAt(j);        
                }
            }
              System.out.print(re1+" "+re2);     
            System.out.println("");    
        }
    }
}

Answer 14

public class PrintCharacters{

public static void main(String args[]) {
    Scanner sc = new Scanner(System.in);
    
    int noOfTestCases = sc.nextInt();
    sc.nextLine();
    String []inputStrings= new String[noOfTestCases];
    for(int i=0;i<noOfTestCases;i++) {
        inputStrings[i]=sc.nextLine();
    }
    
    for(String str: inputStrings) {
        String even ="";
        String odd ="";
        for(int i=0;i<str.length();i++) {
            if(i%2==0) {
                even+=str.charAt(i);
            }else {
                odd+=str.charAt(i);
            }
        }
        System.out.println(even+" "+odd);
    }
    sc.close();
    
}

}


Input: 
  2
  Hacker
  Rank

Output:
  Hce akr
  Rn ak

Answer 15

import java.util.*;

public class Solution {

public static void main(String[] args) {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
    
    Scanner scan=new Scanner(System.in);
    int n=scan.nextInt();
    while(n>0) {
        String str=scan.next();
        for(int i=0;i<str.length();i++) {
            if(i%2==0) {
                System.out.print(str.charAt(i));
            }
        }
        System.out.print(" ");
        for(int i=0;i<str.length();i++) {
            if(i%2==1) {
                System.out.print(str.charAt(i));
            }
        }
        n--;
        System.out.println();
    }
    
    
}

}