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!
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
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();
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. :)
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) )
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); 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.
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();
}
}
}
}
I've solved this question in 2 ways & both are producing correct output.
Have a look & let me know if you've any problem.
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
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
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();
}
** 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'));
});
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();
}
}
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
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);
}
}
}
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("");
}
}
}
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
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();
}
}
}
I try to print every 4 words of my text file with capital letter in console, but this code prints all of my file capital and I can't find out why?
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class FileText {
public static void main(String[] args) {
Scanner sc = null;
try {
sc = new Scanner(new File("players.txt"));
int count = 0;
while (sc.hasNext()) {
String line = sc.next();
String[] elements = line.split(" ");
for (int i = 0; i < elements.length; i++) {
if (i/3 == 0){
System.out.println(elements[i].toUpperCase());
}
else {
System.out.println(elements[i]);
}
}
}
System.out.println("The number of capital letters are: " + count);
} catch (FileNotFoundException e) {
System.out.println(e.getMessage());
}
finally {
sc.close();
}
}
}
There are two things going wrong:
a)
the line String[] elements = line.split(" "); does not split the line at every word. The way you use the Scanner already splits them (because the Scanner's default delimeter is a space), meaning that your line variable always only contains one word.
Fix this by using sc.useDelimeter("\n"); before the while(sc.hasNext()) loop.
b)
replace
if(i/3 == 0){
with
if(i%4 == 0){ //modulo division
here is complete code:
public static void main(String[] args) {
Scanner sc = null;
try {
sc = new Scanner(new File("players.txt"));
int count = 0;
while (sc.hasNextLine()) {
String line = sc.nextLine();
String[] elements = line.split(" ");
for (int i = 0; i < elements.length; i++) {
if ((i+1) % 4 == 0) {
System.out.println(elements[i].toUpperCase());
} else {
System.out.println(elements[i]);
}
}
}
System.out.println("The number of capital letters are: " + count);
} catch (FileNotFoundException e) {
System.out.println(e.getMessage());
} finally {
sc.close();
}
}
For the file with content: w1 w2 w3 w4 w5 w6 w7 w8 w9 w10 w11 w12
output will be:
w1
w2
w3
W4
w5
w6
w7
W8
w9
w10
w11
W12
hi am trying to write a palindrome checker code but if i enter "madam" it still tells me its not a palindrome please help. tell me whats causing it
import java.util.Scanner;
public class parlindrome
{
String original, reverse = "";
public void checkpalindrome(){
Scanner h = new Scanner(System.in);
System.out.println("enter a word : ");
original = h.nextLine();
int length = original.length();
for(int i = length-1; i >= 0; i--)
{
{
reverse = reverse + original.charAt(i);
if(original.equals(reverse))
{
System.out.println("entered word is a palindrom ");
}
else
{
System.out.println("entered word is not a palindrome ");
break;
}
}
}
}
public static void main(String[]args)
{
parlindrome k=new parlindrome();
k.checkpalindrome();
}
}
You should finish the loop that reverses the String before checking if it's a palindrome :
for(int i=length-1;i>=0;i--) {
reverse=reverse+original.charAt(i);
}
if(original.equals(reverse)) {
System.out.println("entered word is a palindrom ");
}
Also, if you want this method to work more than once, you should make reverse a local variable and initialize it to an empty String inside the method.
You could do it in a more effective way, using Java´s reverse.
public void checkpalindrome(){
Scanner h = new Scanner(System.in);
System.out.println("Enter a word: ");
String original = h.nextLine();
if(original.equals(new StringBuilder(original).reverse().toString()))
System.out.println("Entered word is a palindrom");
else
System.out.println("Entered word is not a palindrom");
}
try this:
import java.util.Scanner;
public class parlindrome {
public boolean checkpalindrome(String original) {
String reverse = "";
int length = original.length();
for (int i = length - 1; i >= 0; i--) {
reverse += original.charAt(i);
}
if (reverse.equals(original)) {
System.out.println("entered word is a palindrom ");
return true;
}
System.out.println("entered word is not a palindrom ");
return false;
}
public static void main(String[] args) {
Scanner h = new Scanner(System.in);
System.out.println("enter a word : ");
String original = h.nextLine();
parlindrome k = new parlindrome();
k.checkpalindrome(original);
}
}
Just remove validation part from for loop. Your code should be as below:
for (int i = length - 1; i >= 0; i--)
reverse += original.charAt(i);
if (original.equals(reverse))
System.out.println("entered word is a palindrom ");
else
System.out.println("entered word is not a palindrome ");
h.close();
import java.util.Scanner;
public class Separate {
public static void main(String[] args) {
Scanner user_input = new Scanner( System.in );
String variable;
System.out.print("Enter Variable:");
variable = user_input.next();
Separate(variable);
}
public static void Separate(String str) {
String number = "";
String letter = "";
String symbol = "";
for (int i = 0; i < str.length(); i++) {
char a = str.charAt(i);
if (Character.isDigit(a)) {
number = number + a;
} else {
letter = letter + a;
}
}
System.out.println("Alphabets in string:"+letter);
System.out.println("Numbers in String:"+number);
}
}
Okay, i already have this code which separate the Numbers and Letters that i Input. The problem is, when ever i input Symbols for example (^,+,-,%,*) it also states as a Letter.
What i want to do is to separate the symbol from letters just like what i did on Numbers and Letters and make another output for it.
public static void separate(String string) {
StringBuilder alphabetsBuilder = new StringBuilder();
StringBuilder numbersBuilder = new StringBuilder();
StringBuilder symbolsBuilder = new StringBuilder();
for (int i = 0; i < string.length(); i++) {
char ch = string.charAt(i);
if (Character.isAlphabetic(ch)) {
alphabetsBuilder.append(ch);
} else if (Character.isDigit(ch)) {
numbersBuilder.append(ch);
} else {
symbolsBuilder.append(ch);
}
}
System.out.println("Alphabets in string: " + alphabetsBuilder.toString());
System.out.println("Numbers in String: " + numbersBuilder.toString());
System.out.println("Sysmbols in String: " + symbolsBuilder.toString());
}
You are testing if the character isDigit, else treat it as a letter.
Well, if it is not a digit, all other cases go to else, in your code. Create an else case for those symbols also.
As this reeks of homework, just see the documentation of Character, which had that nice function isDigit.
public static void Separate(String str)
{
String number = "";
String letter = "";
String symbol = "";
for (int i = 0; i < str.length(); i++)
{
char a = str.charAt(i);
if (Character.isDigit(a))
{
number = number + a;
continue;
}
if(Character.isLetter(a))
{
letter = letter + a;
}
else
{
symbol = symbol + a;
}
}
System.out.println("Alphabets in string:"+letter);
System.out.println("Numbers in String:"+number);
}
import java.util.Scanner;
public class Separate {
public static void main(String[] args) {
Scanner user_input = new Scanner( System.in );
String variable;
System.out.print("Enter Variable:");
variable = user_input.next();
Separate(variable);
}
public static void Separate(String str)
{
String number = "";
String letter = "";
String symbol = "";
for (int i = 0; i < str.length(); i++) {
char a = str.charAt(i);
if (Character.isDigit(a)) {
number = number + a;
} else if (Character.isLetter(a)) {
letter = letter + a;
} else {
symbol = symbol + a;
}
}
System.out.println("Alphabets in string:"+letter);
System.out.println("Numbers in String:"+number);
System.out.println("Symbols in String:"+symbol);
}
}