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Facing issue while reading stdin in node

I just registered in HackerEarth and trying to solve the first basic problem: Monk and rotation. When I am running the code by entering single input it works fine but when I submit the solution it does not work.
https://www.hackerearth.com/practice/codemonk/
It seems I am reading the input incorrectly
Can someone please help.
process.stdin.resume();
process.stdin.setEncoding("utf-8");
var stdin_input = "";
process.stdin.on("data", function (input) {
stdin_input += input; // Reading input from STDIN
});
process.stdin.on("end", function () {
let lines = stdin_input.split('\n');
let len = lines.length;
let inputArr = [];
const numberTestCase = lines[0]
const output = new Array()
for (i = 1; i < lines.length; i++) {
let lineInput = lines[i].split(' ');
let noOfElement = 0;
let stepRotation = 0;
let skipLineUpto = 0;
let inputData = false;
if (lineInput.length === 2) {
inputData = true;
noOfElement = lineInput[0]
stepRotation = lineInput[1]
skipLineUpto = parseInt(i) + 2;
}
if (inputData) {
let stringOfArray = lines[i + 1];
let arrayData = stringOfArray.split(' ');
let mod = 0
mod = stepRotation % noOfElement;
if (mod != 0) {
let unReversedArray = arrayData.splice(-mod);
let ff = unReversedArray.concat(arrayData)
inputArr.push(ff.join(' '))
} else {
let ff = arrayData
console.log(ff.join(' '))
inputArr.push(ff.join(' '))
}
}
}
main(inputArr)
});
function main(input) {
process.stdout.write(input.join("\n")); // Writing output to STDOUT
}

When you submit you can see why your code is not valid.
Your solution is for when scenarios where input is 3 lines (1 test case), like in their example, but you can see their test cases where they have inputs of multiple lines (T test cases).
Without any prototype method something like this would work (not working because time exceeded):
let lines = stdin_input.split('\n');
let loops = lines[0];
for(i = 1; i < lines.length; i+=2) {
let steps = lines[i].split(' ')[1];
let arr = lines[i+1].split(' ');
for (j = 0; j < steps; j++) {
var x = arr[arr.length-1], i;
for (k = arr.length-1; k > 0; k--) {
arr[k] = arr[k-1];
}
arr[0] = x;
}
main(arr);
}
With pop() and unshift() only one test case is failing due to time exceeded but should get you close to the final solution:
let lines = stdin_input.split('\n');
let loops = lines[0];
for(i = 1; i < lines.length; i+=2) {
let steps = lines[i].split(' ')[1];
let arr = lines[i+1].split(' ');
for (j = 0; j < steps; j++) {
arr.unshift(arr.pop());
}
main(arr);
}

Doubling each letter in a String in js

I need string Double each letter in a string
abc -> aabbcc
i try this
var s = "abc";
for(var i = 0; i < s.length ; i++){
console.log(s+s);
}
o/p
> abcabc
> abcabc
> abcabc
but i need
aabbcc
help me

Use String#split , Array#map and Array#join methods.
var s = "abc";
console.log(
// split the string into individual char array
s.split('').map(function(v) {
// iterate and update
return v + v;
// join the updated array
}).join('')
)
UPDATE : You can even use String#replace method for that.
var s = "abc";
console.log(
// replace each charcter with repetition of it
// inside substituting string you can use $& for getting matched char
s.replace(/./g, '$&$&')
)

You need to reference the specific character at the index within the string with s[i] rather than just s itself.
var s = "abc";
var out = "";
for(var i = 0; i < s.length ; i++){
out = out + (s[i] + s[i]);
}
console.log(out);

I have created a function which takes string as an input and iterate the string and returns the final string with each character doubled.
var s = "abcdef";
function makeDoubles(s){
var s1 = "";
for(var i=0; i<s.length; i++){
s1 += s[i]+s[i];
}
return s1;
}
alert(makeDoubles(s));

if you want to make it with a loop, then you have to print s[i]+s[i];
not, s + s.
var s = "abc";
let newS = "";
for (var i = 0; i < s.length; i++) {
newS += s[i] + s[i];
}
console.log(newS);
that works for me, maybe a little bit hardcoded, but I am new too))
good luck

console.log(s+s);, here s holds entire string. You will have to fetch individual character and append it.
var s = "abc";
var r = ""
for (var i = 0; i < s.length; i++) {
var c = s.charAt(i);
r+= c+c
}
console.log(r)

var doubleStr = function(str) {
str = str.split('');
var i = 0;
while (i < str.length) {
str.splice(i, 0, str[i]);
i += 2;
}
return str.join('');
};

You can simply use one of these two methods:
const doubleChar = (str) => str.split("").map(c => c + c).join("");
OR
function doubleChar(str) {
var word = '';
for (var i = 0; i < str.length; i++){
word = word + str[i] + str[i];
};
return word;
};

function doubleChar(str) {
let sum = [];
for (let i = 0; i < str.length; i++){
let result = (str[i]+str[i]);
sum = sum + result;
}
return sum;
}
console.log (doubleChar ("Hello"));

How to make characters in a string repeat using Javascript?

How can I make individual characters within a string repeat a given amount of times?
That is, how do I turn "XyZ" into "XXXyyyZZZ"?

Try this:
var foo = 'bar';
function makeString(str, repeat) {
var str = Array.prototype.map.call(str, function(character) {
var nascentStr = '';
while (nascentStr.length < repeat) {
nascentStr += character;
}
return nascentStr;
}).join('');
return str;
}
alert(makeString(foo, 3));

You'll need to use a combination of a few functions. First you'll need to split the string into individual characters:
var charArray = "XyZ".split('');
Once you have it split up, you can use a combination of the .map function and a nifty little trick of javascript Array.
var someMultiplier = 5;
var duplicatedArray = charArray.map(function(char) {
return Array(someMultiplier).join(char);
});
At that point, you have an array of strings that have the duplicate letters, and you can combine them back with .join
var dupString = duplicatedArray.join('');
dupString === "XXXXXyyyyyZZZZZ

Sounds straight forward. You can run this in your browser's console:
var my = 'XyZ';
function repeat(str, times) {
var res = '';
for (var i in str) {
var char = str[i];
for (var j=0; j < times; j++) {
res += char;
}
}
return res;
}
var his = repeat(my, 3);
console.log(his);

you have not mentioned what will happen if input will be like xyxzy. Assuming it will be xxxyyxxxzzzyyy
// function takes input string & num of repitation
function buildString(input, num) {
var _currentChar = ""; // Final output string
for (var m = 0; m < input.length; m++) {
//call another function which will return XXX or yyy or zzz & then finally concat it
_currentChar += _repeatString((input.charAt(m)), num);
}
}
// It will return XXX or yyy or ZZZ
// takes individual char as input and num of times to repeat
function _repeatString(char, num) {
var _r = "";
for (var o = 0; o < num; o++) {
_r += char;
}
return _r
}
buildString('XyZ', 3)
jsfiddle for Example

function repeatStringNumTimes(str, num) {
let valueCopy = str
if (num > 0) {
for (var i = 0; i < num - 1; i++) {
valueCopy = valueCopy.concat(str)
}
} else {
valueCopy = ""
}
return valueCopy;
}
repeatStringNumTimes("abc", 3);

These days can be done a lot easier:
const repeater = (str, n) => [...str].map(c => c.repeat(n)).join('');
alert(repeater('XyZ', 3));

how to reverse string without using any built in functions in javascript

can anyone please tell me how to reverse a given string without using ANY built in functions?
I have tried following ones, but in all cases there is some built in functions involved
function reverseString(str){
return str.split("").reverse().join("");
}
reverseString("I love coding");
function reverseString(str){
var myArray = [];
for(var i = 0; i <= str.length; i++ ){
myArray.push(str.charAt(str.length - i));
}
return myArray.join("");
}
reverseString("I love coding");
function reverseString(str){
var reversedString = '';
for(var i = str.length -1 ; i >= 0; i--){
reversedString += str[i];
}
return reversedString;
}
reverseString("I love coding");
function reverseString(str){
var newArray = [];
for(var i = str.length -1, j = 0; i >= 0; i--, j++){
newArray[j] = str[i];
}
return newArray.join("");
}
reverseString("I love coding");

to comply with requirement of no natives and no var declaration I've cheated.
named arguments can be reassigned.
var s = 'foobar';
function r(e,v,r){
for(r=e.length,v='';r;)v+=e[--r];return v;
}
console.log(r(s));

It is very simple
var name = 'bhaurao';
var newName = '';
for(i in name){
newName = name[i] + newName;
}
console.log("reverse string is "+newName);
You can check example here Click here

Find the characters in a string which are not duplicated

I have to make a function in JavaScript that removes all duplicated letters in a string. So far I've been able to do this: If I have the word "anaconda" it shows me as a result "anaconda" when it should show "cod". Here is my code:
function find_unique_characters( string ){
var unique='';
for(var i=0; i<string.length; i++){
if(unique.indexOf(string[i])==-1){
unique += string[i];
}
}
return unique;
}
console.log(find_unique_characters('baraban'));

We can also now clean things up using filter method:
function removeDuplicateCharacters(string) {
return string
.split('')
.filter(function(item, pos, self) {
return self.indexOf(item) == pos;
})
.join('');
}
console.log(removeDuplicateCharacters('baraban'));
Working example:

function find_unique_characters(str) {
var unique = '';
for (var i = 0; i < str.length; i++) {
if (str.lastIndexOf(str[i]) == str.indexOf(str[i])) {
unique += str[i];
}
}
return unique;
}
console.log(find_unique_characters('baraban'));
console.log(find_unique_characters('anaconda'));
If you only want to return characters that appear occur once in a string, check if their last occurrence is at the same position as their first occurrence.
Your code was returning all characters in the string at least once, instead of only returning characters that occur no more than once. but obviously you know that already, otherwise there wouldn't be a question ;-)

Just wanted to add my solution for fun:
function removeDoubles(string) {
var mapping = {};
var newString = '';
for (var i = 0; i < string.length; i++) {
if (!(string[i] in mapping)) {
newString += string[i];
mapping[string[i]] = true;
}
}
return newString;
}

With lodash:
_.uniq('baraban').join(''); // returns 'barn'

You can put character as parameter which want to remove as unique like this
function find_unique_characters(str, char){
return [...new Set(str.split(char))].join(char);
}
function find_unique_characters(str, char){
return [...new Set(str.split(char))].join(char);
}
let result = find_unique_characters("aaaha ok yet?", "a");
console.log(result);

//One simple way to remove redundecy of Char in String
var char = "aaavsvvssff"; //Input string
var rst=char.charAt(0);
for(var i=1;i<char.length;i++){
var isExist = rst.search(char.charAt(i));
isExist >=0 ?0:(rst += char.charAt(i) );
}
console.log(JSON.stringify(rst)); //output string : avsf

For strings (in one line)
removeDuplicatesStr = str => [...new Set(str)].join('');
For arrays (in one line)
removeDuplicatesArr = arr => [...new Set(arr)]

Using Set:
removeDuplicates = str => [...new Set(str)].join('');
Thanks to David comment below.

DEMO
function find_unique_characters( string ){
unique=[];
while(string.length>0){
var char = string.charAt(0);
var re = new RegExp(char,"g");
if (string.match(re).length===1) unique.push(char);
string=string.replace(re,"");
}
return unique.join("");
}
console.log(find_unique_characters('baraban')); // rn
console.log(find_unique_characters('anaconda')); //cod
​

var str = 'anaconda'.split('');
var rmDup = str.filter(function(val, i, str){
return str.lastIndexOf(val) === str.indexOf(val);
});
console.log(rmDup); //prints ["c", "o", "d"]
Please verify here: https://jsfiddle.net/jmgy8eg9/1/

Using Set() and destructuring twice is shorter:
const str = 'aaaaaaaabbbbbbbbbbbbbcdeeeeefggggg';
const unique = [...new Set([...str])].join('');
console.log(unique);

Yet another way to remove all letters that appear more than once:
function find_unique_characters( string ) {
var mapping = {};
for(var i = 0; i < string.length; i++) {
var letter = string[i].toString();
mapping[letter] = mapping[letter] + 1 || 1;
}
var unique = '';
for (var letter in mapping) {
if (mapping[letter] === 1)
unique += letter;
}
return unique;
}
Live test case.
Explanation: you loop once over all the characters in the string, mapping each character to the amount of times it occurred in the string. Then you iterate over the items (letters that appeared in the string) and pick only those which appeared only once.

function removeDup(str) {
var arOut = [];
for (var i=0; i < str.length; i++) {
var c = str.charAt(i);
if (c === '_') continue;
if (str.indexOf(c, i+1) === -1) {
arOut.push(c);
}
else {
var rx = new RegExp(c, "g");
str = str.replace(rx, '_');
}
}
return arOut.join('');
}

I have FF/Chrome, on which this works:
var h={};
"anaconda".split("").
map(function(c){h[c] |= 0; h[c]++; return c}).
filter(function(c){return h[c] == 1}).
join("")
Which you can reuse if you write a function like:
function nonRepeaters(s) {
var h={};
return s.split("").
map(function(c){h[c] |= 0; h[c]++; return c}).
filter(function(c){return h[c] == 1}).
join("");
}
For older browsers that lack map, filter etc, I'm guessing that it could be emulated by jQuery or prototype...

This code worked for me on removing duplicate(repeated) characters from a string (even if its words separated by space)
Link: Working Sample JSFiddle
/* This assumes you have trim the string and checked if it empty */
function RemoveDuplicateChars(str) {
var curr_index = 0;
var curr_char;
var strSplit;
var found_first;
while (curr_char != '') {
curr_char = str.charAt(curr_index);
/* Ignore spaces */
if (curr_char == ' ') {
curr_index++;
continue;
}
strSplit = str.split('');
found_first = false;
for (var i=0;i<strSplit.length;i++) {
if(str.charAt(i) == curr_char && !found_first)
found_first = true;
else if (str.charAt(i) == curr_char && found_first) {
/* Remove it from the string */
str = setCharAt(str,i,'');
}
}
curr_index++;
}
return str;
}
function setCharAt(str,index,chr) {
if(index > str.length-1) return str;
return str.substr(0,index) + chr + str.substr(index+1);
}

Here's what I used - haven't tested it for spaces or special characters, but should work fine for pure strings:
function uniquereduce(instring){
outstring = ''
instringarray = instring.split('')
used = {}
for (var i = 0; i < instringarray.length; i++) {
if(!used[instringarray[i]]){
used[instringarray[i]] = true
outstring += instringarray[i]
}
}
return outstring
}

Just came across a similar issue (finding the duplicates). Essentially, use a hash to keep track of the character occurrence counts, and build a new string with the "one-hit wonders":
function oneHitWonders(input) {
var a = input.split('');
var l = a.length;
var i = 0;
var h = {};
var r = "";
while (i < l) {
h[a[i]] = (h[a[i]] || 0) + 1;
i += 1;
}
for (var c in h) {
if (h[c] === 1) {
r += c;
}
}
return r;
}
Usage:
var a = "anaconda";
var b = oneHitWonders(a); // b === "cod"

Try this code, it works :)
var str="anaconda";
Array.prototype.map.call(str,
(obj,i)=>{
if(str.indexOf(obj,i+1)==-1 && str.lastIndexOf(obj,i-1)==-1){
return obj;
}
}
).join("");
//output: "cod"

This should work using Regex ;
NOTE: Actually, i dont know how this regex works ,but i knew its 'shorthand' ,
so,i would have Explain to you better about meaning of this /(.+)(?=.*?\1)/g;.
this regex only return to me the duplicated character in an array ,so i looped through it to got the length of the repeated characters .but this does not work for a special characters like "#" "_" "-", but its give you expected result ; including those special characters if any
function removeDuplicates(str){
var REPEATED_CHARS_REGEX = /(.+)(?=.*?\1)/g;
var res = str.match(REPEATED_CHARS_REGEX);
var word = res.slice(0,1);
var raw = res.slice(1);
var together = new String (word+raw);
var fer = together.toString();
var length = fer.length;
// my sorted duplicate;
var result = '';
for(var i = 0; i < str.length; i++) {
if(result.indexOf(str[i]) < 0) {
result += str[i];
}
}
return {uniques: result,duplicates: length};
} removeDuplicates('anaconda')
The regular expression /([a-zA-Z])\1+$/ is looking for:
([a-zA-Z]]) - A letter which it captures in the first group; then
\1+ - immediately following it one or more copies of that letter; then
$ - the end of the string.
Changing it to /([a-zA-Z]).*?\1/ instead searches for:
([a-zA-Z]) - A letter which it captures in the first group; then
.*? - zero or more characters (the ? denotes as few as possible); until
\1 - it finds a repeat of the first matched character.

I have 3 loopless, one-line approaches to this.
Approach 1 - removes duplicates, and preserves original character order:
var str = "anaconda";
var newstr = str.replace(new RegExp("[^"+str.split("").sort().join("").replace(/(.)\1+/g, "").replace(/[.?*+^$[\]\\(){}|-]/g, "\\$&")+"]","g"),"");
//cod
Approach 2 - removes duplicates but does NOT preserve character order, but may be faster than Approach 1 because it uses less Regular Expressions:
var str = "anaconda";
var newstr = str.split("").sort().join("").replace(/(.)\1+/g, "");
//cdo
Approach 3 - removes duplicates, but keeps the unique values (also does not preserve character order):
var str = "anaconda";
var newstr = str.split("").sort().join("").replace(/(.)(?=.*\1)/g, "");
//acdno

function removeduplicate(str) {
let map = new Map();
// n
for (let i = 0; i < str.length; i++) {
if (map.has(str[i])) {
map.set(str[i], map.get(str[i]) + 1);
} else {
map.set(str[i], 1);
}
}
let res = '';
for (let i = 0; i < str.length; i++) {
if (map.get(str[i]) === 1) {
res += str[i];
}
}
// o (2n) - > O(n)
// space o(n)
return res;
}

If you want your function to just return you a unique set of characters in your argument, this piece of code might come in handy.
Here, you can also check for non-unique values which are being recorded in 'nonUnique' titled array:
function remDups(str){
if(!str.length)
return '';
var obj = {};
var unique = [];
var notUnique = [];
for(var i = 0; i < str.length; i++){
obj[str[i]] = (obj[str[i]] || 0) + 1;
}
Object.keys(obj).filter(function(el,ind){
if(obj[el] === 1){
unique+=el;
}
else if(obj[el] > 1){
notUnique+=el;
}
});
return unique;
}
console.log(remDups('anaconda')); //prints 'cod'
If you want to return the set of characters with their just one-time occurrences in the passed string, following piece of code might come in handy:
function remDups(str){
if(!str.length)
return '';
var s = str.split('');
var obj = {};
for(var i = 0; i < s.length; i++){
obj[s[i]] = (obj[s[i]] || 0) + 1;
}
return Object.keys(obj).join('');
}
console.log(remDups('anaconda')); //prints 'ancod'

function removeDuplicates(str) {
var result = "";
var freq = {};
for(i=0;i<str.length;i++){
let char = str[i];
if(freq[char]) {
freq[char]++;
} else {
freq[char] =1
result +=char;
}
}
return result;
}

console.log(("anaconda").split('').sort().join('').replace(/(.)\1+/g, ""));
By this, you can do it in one line.
output: 'cdo'

function removeDuplicates(string){
return string.split('').filter((item, pos, self)=> self.indexOf(item) == pos).join('');
}
the filter will remove all characters has seen before using the index of item and position of the current element

Method 1 : one Simple way with just includes JS- function
var data = 'sssssddddddddddfffffff';
var ary = [];
var item = '';
for (const index in data) {
if (!ary.includes(data[index])) {
ary[index] = data[index];
item += data[index];
}
}
console.log(item);
Method 2 : Yes we can make this possible without using JavaScript function :
var name = 'sssssddddddddddfffffff';
let i = 0;
let newarry = [];
for (let singlestr of name) {
newarry[i] = singlestr;
i++;
}
// now we have new Array and length of string
length = i;
function getLocation(recArray, item, arrayLength) {
firstLaction = -1;
for (let i = 0; i < arrayLength; i++) {
if (recArray[i] === item) {
firstLaction = i;
break;
}
}
return firstLaction;
}
let finalString = '';
for (let b = 0; b < length; b++) {
const result = getLocation(newarry, newarry[b], length);
if (result === b) {
finalString += newarry[b];
}
}
console.log(finalString); // sdf

// Try this way
const str = 'anaconda';
const printUniqueChar = str => {
const strArr = str.split("");
const uniqueArray = strArr.filter(el => {
return strArr.indexOf(el) === strArr.lastIndexOf(el);
});
return uniqueArray.join("");
};
console.log(printUniqueChar(str)); // output-> cod

function RemDuplchar(str)
{
var index={},uniq='',i=0;
while(i<str.length)
{
if (!index[str[i]])
{
index[str[i]]=true;
uniq=uniq+str[i];
}
i++;
}
return uniq;
}

We can remove the duplicate or similar elements in string using for loop and extracting string methods like slice, substring, substr
Example if you want to remove duplicate elements such as aababbafabbb:
var data = document.getElementById("id").value
for(var i = 0; i < data.length; i++)
{
for(var j = i + 1; j < data.length; j++)
{
if(data.charAt(i)==data.charAt(j))
{
data = data.substring(0, j) + data.substring(j + 1);
j = j - 1;
console.log(data);
}
}
}
Please let me know if you want some additional information.