From 72e69c2ac66a0b77cfbbf9b1645c0870583cda55 Mon Sep 17 00:00:00 2001
From: Roman Tarasenko <taras.rd54@gmail.com>
Date: Mon, 3 Aug 2020 16:31:43 +0300
Subject: [PATCH 1/6] Adds 1-4 tasks solutions

---
 task/01-strings-tasks.js |  54 ++++++++----
 task/02-numbers-tasks.js |  40 ++++++---
 task/03-date-tasks.js    |  40 +++++++--
 task/04-arrays-tasks.js  | 185 ++++++++++++++++++++++++++++++++-------
 4 files changed, 252 insertions(+), 67 deletions(-)

diff --git a/task/01-strings-tasks.js b/task/01-strings-tasks.js
index e28054657..82b6d598a 100644
--- a/task/01-strings-tasks.js
+++ b/task/01-strings-tasks.js
@@ -22,7 +22,7 @@
  *   '',  'bb'  => 'bb'
  */
 function concatenateStrings(value1, value2) {
-    throw new Error('Not implemented');
+    return value1+value2;
 }
 
 
@@ -38,7 +38,7 @@ function concatenateStrings(value1, value2) {
  *   ''      => 0
  */
 function getStringLength(value) {
-    throw new Error('Not implemented');
+    return value.length;
 }
 
 /**
@@ -55,7 +55,7 @@ function getStringLength(value) {
  *   'Chuck','Norris'  => 'Hello, Chuck Norris!'
  */
 function getStringFromTemplate(firstName, lastName) {
-    throw new Error('Not implemented');
+    return `Hello, ${firstName} ${lastName}!`;
 }
 
 /**
@@ -69,7 +69,7 @@ function getStringFromTemplate(firstName, lastName) {
  *   'Hello, Chuck Norris!' => 'Chuck Norris'
  */
 function extractNameFromTemplate(value) {
-    throw new Error('Not implemented');
+    return value.substring(7,value.length-1);
 }
 
 
@@ -84,7 +84,7 @@ function extractNameFromTemplate(value) {
  *   'cat'       => 'c'
  */
 function getFirstChar(value) {
-    throw new Error('Not implemented');
+    return value.substring(0,1);
 }
 
 /**
@@ -99,7 +99,7 @@ function getFirstChar(value) {
  *   '\tHello, World! ' => 'Hello, World!'
  */
 function removeLeadingAndTrailingWhitespaces(value) {
-    throw new Error('Not implemented');
+    return value.trim();
 }
 
 /**
@@ -114,7 +114,7 @@ function removeLeadingAndTrailingWhitespaces(value) {
  *   'cat', 3 => 'catcatcat'
  */
 function repeatString(value, count) {
-    throw new Error('Not implemented');
+    return value.repeat(count);
 }
 
 /**
@@ -130,7 +130,7 @@ function repeatString(value, count) {
  *   'ABABAB','BA' => 'ABAB'
  */
 function removeFirstOccurrences(str, value) {
-    throw new Error('Not implemented');
+    return str.replace(value, "");
 }
 
 /**
@@ -145,7 +145,7 @@ function removeFirstOccurrences(str, value) {
  *   '<a>' => 'a'
  */
 function unbracketTag(str) {
-    throw new Error('Not implemented');
+    return str.replace(/[\<\>]+/g, "");
 }
 
 
@@ -160,7 +160,7 @@ function unbracketTag(str) {
  *  'abcdefghijklmnopqrstuvwxyz' => 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
  */
 function convertToUpperCase(str) {
-    throw new Error('Not implemented');
+    return str.toLocaleUpperCase();
 }
 
 /**
@@ -174,7 +174,7 @@ function convertToUpperCase(str) {
  *   'info@gmail.com' => ['info@gmail.com']
  */
 function extractEmails(str) {
-    throw new Error('Not implemented');
+    return str.split(";") ;
 }
 
 /**
@@ -201,7 +201,12 @@ function extractEmails(str) {
  *
  */
 function getRectangleString(width, height) {
-    throw new Error('Not implemented');
+    let top = `┌${'─'.repeat(width -2)}┐\n` ;
+    let side = `│${' '.repeat(width -2)}│\n`;
+    let bottom = `└${'─'.repeat(width -2)}┘\n`;
+
+    console.log(top + side.repeat(height - 2) + bottom)
+    return top + side.repeat(height - 2) + bottom;
 }
 
 
@@ -221,7 +226,11 @@ function getRectangleString(width, height) {
  *
  */
 function encodeToRot13(str) {
-    throw new Error('Not implemented');
+  let input = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
+  let output = 'NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm';
+  let index = x => input.indexOf(x);
+  let translate = x => index(x) > -1 ? output[index(x)] : x;
+  return str.split('').map(translate).join('');
 }
 
 /**
@@ -238,7 +247,14 @@ function encodeToRot13(str) {
  *   isString(new String('test')) => true
  */
 function isString(value) {
-    throw new Error('Not implemented');
+    let val;
+    if (typeof value === 'string') {
+        val = value;
+    }
+    if (typeof value === 'object' && value !== null && !Array.isArray(value)) {
+        val = value.valueOf()
+    }
+    return (typeof val === 'string')
 }
 
 
@@ -267,9 +283,15 @@ function isString(value) {
  *   'K♠' => 51
  */
 function getCardId(value) {
-    throw new Error('Not implemented');
-}
+    const cards = [
+        'A♣','2♣','3♣','4♣','5♣','6♣','7♣','8♣','9♣','10♣','J♣','Q♣','K♣',
+        'A♦','2♦','3♦','4♦','5♦','6♦','7♦','8♦','9♦','10♦','J♦','Q♦','K♦',
+        'A♥','2♥','3♥','4♥','5♥','6♥','7♥','8♥','9♥','10♥','J♥','Q♥','K♥',
+        'A♠','2♠','3♠','4♠','5♠','6♠','7♠','8♠','9♠','10♠','J♠','Q♠','K♠'
+    ];
 
+    return cards.indexOf(value);
+}
 
 module.exports = {
     concatenateStrings: concatenateStrings,
diff --git a/task/02-numbers-tasks.js b/task/02-numbers-tasks.js
index c9ed20208..aaff3a95f 100644
--- a/task/02-numbers-tasks.js
+++ b/task/02-numbers-tasks.js
@@ -22,7 +22,7 @@
  *   5, 5  => 25
  */
 function getRectangleArea(width, height) {
-    throw new Error('Not implemented');
+    return width * height;
 }
 
 
@@ -38,7 +38,7 @@ function getRectangleArea(width, height) {
  *   0    => 0
  */
 function getCicleCircumference(radius) {
-    throw new Error('Not implemented');
+    return 2*Math.sqrt*radius;
 }
 
 /**
@@ -54,7 +54,10 @@ function getCicleCircumference(radius) {
  *  -3, 3  => 0
  */
 function getAverage(value1, value2) {
-    throw new Error('Not implemented');
+    if (value1 === value2) {
+        return value1
+    }
+    return ((value1 + value2) / 2);
 }
 
 /**
@@ -73,7 +76,7 @@ function getAverage(value1, value2) {
  *   (-5,0) (10,-10) => 18.027756377319946
  */
 function getDistanceBetweenPoints(x1, y1, x2, y2) {
-    throw new Error('Not implemented');
+    return Math.sqrt(((x2-x1)**2) +((y2-y1)**2));
 }
 
 /**
@@ -89,7 +92,7 @@ function getDistanceBetweenPoints(x1, y1, x2, y2) {
  *   5*x = 0         => 0
  */
 function getLinearEquationRoot(a, b) {
-    throw new Error('Not implemented');
+    return ((-b)/a);
 }
 
 
@@ -111,7 +114,7 @@ function getLinearEquationRoot(a, b) {
  *   (0,1) (1,2)     => 0
  */
 function getAngleBetweenVectors(x1, y1, x2, y2) {
-    throw new Error('Not implemented');
+    return Math.abs(Math.atan(y1 / x1) - Math.atan(y2 / x2))
 }
 
 /**
@@ -127,7 +130,8 @@ function getAngleBetweenVectors(x1, y1, x2, y2) {
  *     0     => 0
  */
 function getLastDigit(value) {
-    throw new Error('Not implemented');
+    const lastChar = value.toString()[value.toString().length - 1];
+    return +lastChar;
 }
 
 
@@ -143,7 +147,7 @@ function getLastDigit(value) {
  * '-525.5'     => -525.5
  */
 function parseNumberFromString(value) {
-    throw new Error('Not implemented');
+    return +value
 }
 
 /**
@@ -160,7 +164,7 @@ function parseNumberFromString(value) {
  *   1,2,3   => 3.741657386773941
  */
 function getParallelipidedDiagonal(a,b,c) {
-    throw new Error('Not implemented');
+    return Math.sqrt((a**2 + b**2) + c**2)
 }
 
 /**
@@ -181,7 +185,10 @@ function getParallelipidedDiagonal(a,b,c) {
  *   1678, 3  => 2000
  */
 function roundToPowerOfTen(num, pow) {
-    throw new Error('Not implemented');
+    if (pow === 0){
+        return num;
+    }
+    return Math.round(num/(10**pow)) * 10**pow;
 }
 
 /**
@@ -202,7 +209,13 @@ function roundToPowerOfTen(num, pow) {
  *   17 => true
  */
 function isPrime(n) {
-    throw new Error('Not implemented');
+    for(let i = 2; i < n; i++) {
+        console.log(n, i)
+        if(n % i === 0) {
+            return false;
+        }
+    }
+    return n > 1;
 }
 
 /**
@@ -221,7 +234,10 @@ function isPrime(n) {
  *   toNumber(new Number(42), 0) => 42
  */
 function toNumber(value, def) {
-    throw new Error('Not implemented');
+    if (value !== null && Number.isInteger(+value)) {
+        return +value
+    }
+    return def;
 }
 
 module.exports = {
diff --git a/task/03-date-tasks.js b/task/03-date-tasks.js
index 83c6266bc..7ab3854d3 100644
--- a/task/03-date-tasks.js
+++ b/task/03-date-tasks.js
@@ -22,7 +22,7 @@
  *    'Sun, 17 May 1998 03:00:00 GMT+01' => Date()
  */
 function parseDataFromRfc2822(value) {
-   throw new Error('Not implemented');
+   return Date.parse(value) ;
 }
 
 /**
@@ -37,7 +37,7 @@ function parseDataFromRfc2822(value) {
  *    '2016-01-19T08:07:37Z' => Date()
  */
 function parseDataFromIso8601(value) {
-   throw new Error('Not implemented');
+   return Date.parse(value);
 }
 
 
@@ -56,7 +56,14 @@ function parseDataFromIso8601(value) {
  *    Date(2015,1,1)    => false
  */
 function isLeapYear(date) {
-   throw new Error('Not implemented');
+   let year = date.getFullYear();
+   if (year % 400 === 0 || year % 100 !==0){
+      if (year % 4 ===0){
+         return true;
+      }
+   }
+   return false;
+   
 }
 
 
@@ -76,7 +83,26 @@ function isLeapYear(date) {
  *    Date(2000,1,1,10,0,0),  Date(2000,1,1,15,20,10,453)   => "05:20:10.453"
  */
 function timeSpanToString(startDate, endDate) {
-   throw new Error('Not implemented');
+   let hours = (endDate.getDay() - startDate.getDay()) * 24 + endDate.getHours() - startDate.getHours();
+      if (hours < 10){
+         hours = '0' + hours;
+      }
+   let minutes = endDate.getMinutes() - startDate.getMinutes();
+      if (minutes < 10){
+         minutes = '0' + minutes;
+      }
+   let seconds = endDate.getSeconds() - startDate.getSeconds();
+      if (seconds < 10){
+         seconds = '0' + seconds;
+      }
+   let milliseconds = endDate.getMilliseconds() - startDate.getMilliseconds();
+      if (milliseconds < 100 && milliseconds >= 10){
+         milliseconds = '0' + milliseconds;
+      }
+      if (milliseconds < 10){
+         milliseconds = '00' + milliseconds
+      };
+   return `${hours}:${minutes}:${seconds}.${milliseconds}`;
 }
 
 
@@ -94,7 +120,11 @@ function timeSpanToString(startDate, endDate) {
  *    Date.UTC(2016,3,5,21, 0) => Math.PI/2
  */
 function angleBetweenClockHands(date) {
-    throw new Error('Not implemented');
+   const hour = date.getUTCHours() > 12 ? date.getUTCHours() - 12 : date.getUTCHours();
+   const minutes = date.getUTCMinutes() * 6;
+   const hours = 0.5 * (60 * hour + date.getUTCMinutes());
+   const angle = hours - minutes > 180 ? hours - minutes - 180 : hours - minutes;
+   return (Math.abs(angle) * Math.PI)/180;
 }
 
 
diff --git a/task/04-arrays-tasks.js b/task/04-arrays-tasks.js
index ff3a4c019..374e1c93e 100644
--- a/task/04-arrays-tasks.js
+++ b/task/04-arrays-tasks.js
@@ -23,7 +23,11 @@
  *    [0, 1, 2, 3, 4, 5], 5    => 5
  */
 function findElement(arr, value) {
-   throw new Error('Not implemented');
+   if (arr.find((el) => el === value)) {
+      return arr.indexOf(value);
+   } else {
+      return '-1'
+   }
 }
 
 /**
@@ -38,7 +42,8 @@ function findElement(arr, value) {
  *    5 => [ 1, 3, 5, 7, 9 ]
  */
 function generateOdds(len) {
-   throw new Error('Not implemented');
+   let arr = new Array(len).fill(2);
+   return arr.map((el, i) => el * i + 1);
 }
 
 
@@ -54,7 +59,7 @@ function generateOdds(len) {
  *    [] => [] 
  */
 function doubleArray(arr) {
-   throw new Error('Not implemented');
+   return arr.concat(arr);
 }
 
 
@@ -70,7 +75,13 @@ function doubleArray(arr) {
  *    [] => [] 
  */
 function getArrayOfPositives(arr) {
-   throw new Error('Not implemented');
+   let arrPos = [];  
+   arr.map((el)=>{
+      if(el > 0){
+         arrPos.push(el)
+      }
+   });
+   return arrPos;
 }
 
 /**
@@ -85,7 +96,8 @@ function getArrayOfPositives(arr) {
  *    [ 'cat, 'dog', 'raccon' ] => [ 'cat', 'dog', 'racoon' ]
  */
 function getArrayOfStrings(arr) {
-   throw new Error('Not implemented');
+   return arr.filter((el) => typeof el === "string");
+   
 }
 
 /**
@@ -101,8 +113,14 @@ function getArrayOfStrings(arr) {
  *    [ 1, 2, 3, 4, 5, 'false' ]         => [ 1, 2, 3, 4, 5, 'false' ]
  *    [ false, 0, NaN, '', undefined ]   => [ ]
  */
-function removeFalsyValues(arr) {
-   throw new Error('Not implemented');
+function removeFalsyValues(arr){
+   let newArr = [];
+   arr.map((el) =>{
+         if (Boolean(el) !== false){
+         newArr.push(el);
+      }
+   })
+   return newArr;
 }
 
 /**
@@ -116,7 +134,7 @@ function removeFalsyValues(arr) {
  *    [ 'a', 'b', 'c', 'd', 'e', 'f', 'g' ]  => [ 'A', 'B', 'C', 'D', 'E', 'F', 'G' ]
  */
 function getUpperCaseStrings(arr) {
-   throw new Error('Not implemented');
+      return arr.map((index) => index.toUpperCase());
 }
 
 
@@ -131,7 +149,7 @@ function getUpperCaseStrings(arr) {
  *    [ 'angular', 'react', 'ember' ] => [ 7, 5, 5 ]
  */
 function getStringsLength(arr) {
-   throw new Error('Not implemented');
+   return arr.map((el) => el.length);
 }
 
 /**
@@ -146,7 +164,7 @@ function getStringsLength(arr) {
  *    [ 1, 'b', 'c'], 0, 'x'  => [ 'x', 1, 'b', 'c' ]
  */
 function insertItem(arr, item, index) {
-   throw new Error('Not implemented');
+   return arr.splice(index, 0, item);
 }
 
 /**
@@ -160,7 +178,8 @@ function insertItem(arr, item, index) {
  *    [ 'a', 'b', 'c', 'd'], 3  => [ 'a', 'b', 'c' ]
  */
 function getHead(arr, n) {
-   throw new Error('Not implemented');
+   arr.length = n;
+   return arr;
 }
 
 
@@ -175,7 +194,7 @@ function getHead(arr, n) {
  *    [ 'a', 'b', 'c', 'd'], 3  => [ 'b', 'c', 'd' ]
  */
 function getTail(arr, n) {
-   throw new Error('Not implemented');
+   return arr.splice(arr.length - n, n);
 }
 
 
@@ -200,7 +219,7 @@ function getTail(arr, n) {
  *    +'30,31,32,33,34'
  */
 function toCsvText(arr) {
-   throw new Error('Not implemented');
+   return arr.map((el) => el.join(",")).join("\n");
 }
 
 /**
@@ -215,7 +234,7 @@ function toCsvText(arr) {
  *   [ 10, 100, -1 ]      => [ 100, 10000, 1 ]
  */
 function toArrayOfSquares(arr) {
-   throw new Error('Not implemented');
+   return arr.map((el) => el * el);
 }
 
 
@@ -234,7 +253,12 @@ function toArrayOfSquares(arr) {
  *   [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ] => [ 1, 3, 6, 10, 15, 21, 28, 36, 45, 55 ]
  */
 function getMovingSum(arr) {
-   throw new Error('Not implemented');
+   let newArr = [];
+   arr.reduce((accum, curr) =>{
+      newArr.push(accum + curr);
+      return accum + curr;
+   }, 0);
+   return newArr;
 }
 
 /**
@@ -249,7 +273,13 @@ function getMovingSum(arr) {
  * [ "a" ] => []
  */
 function getSecondItems(arr) {
-   throw new Error('Not implemented');
+   let newArr = [];
+   arr.map((el) =>{
+      if (arr.indexOf(el) % 2 !== 0){
+         newArr.push(el);
+      }
+   });
+   return newArr;
 }
 
 
@@ -268,7 +298,15 @@ function getSecondItems(arr) {
  *  [ 1,2,3,4,5 ] => [ 1, 2,2, 3,3,3, 4,4,4,4, 5,5,5,5,5 ]
  */
 function propagateItemsByPositionIndex(arr) {
-   throw new Error('Not implemented');
+   let newArr = [];
+   arr.map((el, index) =>{
+      if (index + 1 > 1){
+        newArr = newArr.concat(Array(index + 1).fill(el))
+      } else {
+         newArr.push(el);
+      }
+   });
+   return newArr;
 }
 
 
@@ -286,12 +324,16 @@ function propagateItemsByPositionIndex(arr) {
  *   [ 10, 10, 10, 10 ] => [ 10, 10, 10 ]
  */
 function get3TopItems(arr) {
-   throw new Error('Not implemented');
+   let newArr = arr.reverse();
+   if (arr.length > 3) {
+      newArr.length = 3;
+   }
+   return newArr;
 }
  
  
 /**  
- * Returns the number of positive numbers from specified array
+ *    
  * 
  * @param {array} arr
  * @return {number}
@@ -304,7 +346,15 @@ function get3TopItems(arr) {
  *   [ 1, '2' ] => 1
  */
 function getPositivesCount(arr) {
-   throw new Error('Not implemented');
+   let newArr = [];
+   if (arr.length) {
+      arr.map((el) => {
+         if (typeof el === "number" && el > 0) {
+            newArr.push(el)
+         }
+      });
+   }
+   return newArr.length;
 }
  
 /** 
@@ -321,7 +371,8 @@ function getPositivesCount(arr) {
  *   [ 'one','one','one','zero' ]     => [ 'zero','one','one','one' ]
  */
 function sortDigitNamesByNumericOrder(arr) {
-   throw new Error('Not implemented');
+   const newArr = ['zero', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine'];
+   return arr.sort((a, b) => newArr.indexOf(a) - newArr.indexOf(b));
 }
 
 /** 
@@ -337,7 +388,10 @@ function sortDigitNamesByNumericOrder(arr) {
  *   [ 1, 10, 100, 1000 ]  => 1111
  */
 function getItemsSum(arr) {
-   throw new Error('Not implemented');
+   if (arr.length){
+      return arr.reduce((accum, curr) =>accum + curr);
+   }
+   return 0;
 }
  
 /** 
@@ -353,7 +407,15 @@ function getItemsSum(arr) {
  *  [ null, undefined, NaN, false, 0, '' ]  => 6
  */
 function getFalsyValuesCount(arr) {
-   throw new Error('Not implemented');
+   let newArr = [];
+   if (arr.length){
+      arr.map((el) =>{
+         if (Boolean(el) === false){
+            newArr.push(el);
+         }
+      });
+   }
+   return newArr.length;
 }
 
 /**
@@ -371,7 +433,13 @@ function getFalsyValuesCount(arr) {
  *    [ true, 0, 1, 'true' ], true => 1
  */
 function findAllOccurences(arr, item) {
-   throw new Error('Not implemented');
+   let newArr = [];
+   arr.map ((el) =>{
+      if (el === item){
+         newArr.push(el);
+      }
+   });
+   return newArr.length;
 }
 
 /**
@@ -386,7 +454,7 @@ function findAllOccurences(arr, item) {
  *    ['rock', 'paper', 'scissors']     => 'rock,paper,scissors'
  */
 function toStringList(arr) {
-   throw new Error('Not implemented');
+   return arr.join(',');
 }
 
 
@@ -415,7 +483,18 @@ function toStringList(arr) {
  *      { country: 'Russia',  city: 'Saint Petersburg' }
  */
 function sortCitiesArray(arr) {
-   throw new Error('Not implemented');
+   return arr.sort((a, b) => {
+      if (a.country > b.country) {
+         return 1
+      }
+      return -1
+   }).sort((a, b) => {
+      if (a.country === b.country && a.city < b.city) {
+         return 1
+      } else {
+         return -1
+      }
+    }).reverse();
 }
 
 /**
@@ -437,8 +516,8 @@ function sortCitiesArray(arr) {
  *           [0,0,0,0,1]]   
  */
 function getIdentityMatrix(n) {
-   throw new Error('Not implemented');
-}
+  return Array(n).fill(Array(n).fill()).map((arr, arrIndex) => arr.map((arrEl, elIndex) => arrIndex === elIndex ? 1 : 0))
+ }
 
 /**
  * Creates an array of integers from the specified start to end (inclusive)
@@ -454,7 +533,19 @@ function getIdentityMatrix(n) {
  *     3, 3   => [ 3 ]
  */
 function getIntervalArray(start, end) {
-   throw new Error('Not implemented');
+   let arr = new Array(end - start + 1).fill('i')
+   let element = start;
+   let newArr = [];
+   arr.map((el) => {
+      if (arr.indexOf(el) === 0) {
+         arr[0] = start;
+         newArr.push(start);
+      } else {
+         element += 1;
+         newArr.push(element)
+      }
+   });
+   return newArr;
 }
 
 /**
@@ -469,7 +560,14 @@ function getIntervalArray(start, end) {
  *   [ 1, 1, 2, 2, 3, 3, 4, 4] => [ 1, 2, 3, 4]
  */
 function distinct(arr) {
-   throw new Error('Not implemented');
+   let newArr = [];
+   arr.map((el) =>{
+      let i = newArr.find(item => item === el);
+      if (i === undefined){
+         newArr.push(el);
+      }
+   });
+   return newArr;
 }
 
 /**
@@ -503,7 +601,17 @@ function distinct(arr) {
  *   }
  */
 function group(array, keySelector, valueSelector) {
-   throw new Error('Not implemented');
+   let newArr = []
+   array.map((el) => {
+      const doubleEl = newArr.find(item => item[0] === keySelector(el))
+      if (doubleEl === undefined) {
+         newArr.push([keySelector(el)])
+      }
+   })
+   return newArr.map((el) => {
+      el.push(array.filter(item => keySelector(item) === el[0]).map(item => valueSelector(item)))
+      return el
+   })
 }
 
 
@@ -519,7 +627,13 @@ function group(array, keySelector, valueSelector) {
  *   ['one','two','three'], x=>x.split('')  =>   ['o','n','e','t','w','o','t','h','r','e','e']
  */
 function selectMany(arr, childrenSelector) {
-    throw new Error('Not implemented');
+   let newArr = [];
+   arr.map((el, index) => {
+      (childrenSelector(arr[index]).map((item) => {
+         newArr.push(item)
+      }))
+   })
+   return newArr;
 }
 
 
@@ -536,7 +650,7 @@ function selectMany(arr, childrenSelector) {
  *   [[[ 1, 2, 3]]], [ 0, 0, 1 ]      => 2        (arr[0][0][1])
  */
 function getElementByIndexes(arr, indexes) {
-    throw new Error('Not implemented');
+   return indexes.reduce((prev, curr) => prev[curr], arr)
 }
 
 
@@ -559,7 +673,10 @@ function getElementByIndexes(arr, indexes) {
  * 
  */
 function swapHeadAndTail(arr) {
-    throw new Error('Not implemented');
+   const middle = Math.floor(arr.length/2);
+   const head = arr.splice(0, middle);
+   const tail = arr.splice(arr.length - middle);
+   return [...tail, ...arr, ...head];
 }
 
 

From e65be69ca28754f2cd615d6094b1ab1f7cebcc7f Mon Sep 17 00:00:00 2001
From: Roman Tarasenko <taras.rd54@gmail.com>
Date: Mon, 3 Aug 2020 16:38:43 +0300
Subject: [PATCH 2/6] Adds correction to getDistanceBetweenPoints function

---
 task/02-numbers-tasks.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/task/02-numbers-tasks.js b/task/02-numbers-tasks.js
index aaff3a95f..c9b5ca3cf 100644
--- a/task/02-numbers-tasks.js
+++ b/task/02-numbers-tasks.js
@@ -76,7 +76,7 @@ function getAverage(value1, value2) {
  *   (-5,0) (10,-10) => 18.027756377319946
  */
 function getDistanceBetweenPoints(x1, y1, x2, y2) {
-    return Math.sqrt(((x2-x1)**2) +((y2-y1)**2));
+    return Math.sqrt(((x2-x1)*(x2-x1)) +((y2-y1)*(y2-y1)));
 }
 
 /**

From c8486f9659b2c06210fc14ddc7320531fab7590e Mon Sep 17 00:00:00 2001
From: Roman Tarasenko <taras.rd54@gmail.com>
Date: Mon, 3 Aug 2020 16:56:10 +0300
Subject: [PATCH 3/6] Deletes console.logs, corrects functions

---
 task/01-strings-tasks.js | 3 +--
 task/02-numbers-tasks.js | 7 +++----
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/task/01-strings-tasks.js b/task/01-strings-tasks.js
index 82b6d598a..8dc144aff 100644
--- a/task/01-strings-tasks.js
+++ b/task/01-strings-tasks.js
@@ -204,8 +204,7 @@ function getRectangleString(width, height) {
     let top = `┌${'─'.repeat(width -2)}┐\n` ;
     let side = `│${' '.repeat(width -2)}│\n`;
     let bottom = `└${'─'.repeat(width -2)}┘\n`;
-
-    console.log(top + side.repeat(height - 2) + bottom)
+    
     return top + side.repeat(height - 2) + bottom;
 }
 
diff --git a/task/02-numbers-tasks.js b/task/02-numbers-tasks.js
index c9b5ca3cf..9f5c6df6d 100644
--- a/task/02-numbers-tasks.js
+++ b/task/02-numbers-tasks.js
@@ -38,7 +38,7 @@ function getRectangleArea(width, height) {
  *   0    => 0
  */
 function getCicleCircumference(radius) {
-    return 2*Math.sqrt*radius;
+    return 2 * Math.PI * radius;
 }
 
 /**
@@ -164,7 +164,7 @@ function parseNumberFromString(value) {
  *   1,2,3   => 3.741657386773941
  */
 function getParallelipidedDiagonal(a,b,c) {
-    return Math.sqrt((a**2 + b**2) + c**2)
+    return Math.sqrt((a*a + b*b) + c*c)
 }
 
 /**
@@ -188,7 +188,7 @@ function roundToPowerOfTen(num, pow) {
     if (pow === 0){
         return num;
     }
-    return Math.round(num/(10**pow)) * 10**pow;
+    return Math.round(num/Math.pow(10, pow)) * Math.pow(10, pow);
 }
 
 /**
@@ -210,7 +210,6 @@ function roundToPowerOfTen(num, pow) {
  */
 function isPrime(n) {
     for(let i = 2; i < n; i++) {
-        console.log(n, i)
         if(n % i === 0) {
             return false;
         }

From 731477376669f0207517f9c832ea6050343a3ff8 Mon Sep 17 00:00:00 2001
From: Roman Tarasenko <taras.rd54@gmail.com>
Date: Mon, 3 Aug 2020 17:07:52 +0300
Subject: [PATCH 4/6] Corrects function sorting

---
 task/04-arrays-tasks.js | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/task/04-arrays-tasks.js b/task/04-arrays-tasks.js
index 374e1c93e..81c87c679 100644
--- a/task/04-arrays-tasks.js
+++ b/task/04-arrays-tasks.js
@@ -484,17 +484,11 @@ function toStringList(arr) {
  */
 function sortCitiesArray(arr) {
    return arr.sort((a, b) => {
-      if (a.country > b.country) {
-         return 1
+      if (a.country === b.country) {
+         return a.city > b.city ? 1 : -1;
       }
-      return -1
-   }).sort((a, b) => {
-      if (a.country === b.country && a.city < b.city) {
-         return 1
-      } else {
-         return -1
-      }
-    }).reverse();
+      return a.country > b.country ? 1 : -1
+   });
 }
 
 /**

From 70c17f505a51816e9289a769676a9f49e978cf3c Mon Sep 17 00:00:00 2001
From: Roman Tarasenko <taras.rd54@gmail.com>
Date: Mon, 3 Aug 2020 17:17:16 +0300
Subject: [PATCH 5/6] adds fix

---
 task/04-arrays-tasks.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/task/04-arrays-tasks.js b/task/04-arrays-tasks.js
index 81c87c679..bb1670da5 100644
--- a/task/04-arrays-tasks.js
+++ b/task/04-arrays-tasks.js
@@ -333,7 +333,7 @@ function get3TopItems(arr) {
  
  
 /**  
- *    
+ * Returns the number of positive numbers from specified array
  * 
  * @param {array} arr
  * @return {number}

From c4383183969e6cd792af9b2811bb42871e9da444 Mon Sep 17 00:00:00 2001
From: Roman Tarasenko <taras.rd54@gmail.com>
Date: Mon, 3 Aug 2020 17:33:54 +0300
Subject: [PATCH 6/6] Adds repo name fixes

---
 README.md    | 4 ++--
 package.json | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/README.md b/README.md
index 79f9dff75..4ba6d87c7 100644
--- a/README.md
+++ b/README.md
@@ -29,7 +29,7 @@ To start javascript assignments please follow the next steps:
   git commit -m "Update the links"
   git push origin master
 ```
-* Open https://github.com/rolling-scopes-school/js-assignments and test the build icon. Now it will run all tests and update status once you push changes to github. Keep this icon green!
+* Open https://github.com/RomanTarasenko/js-assignments and test the build icon. Now it will run all tests and update status once you push changes to github. Keep this icon green!
 
 
 ### How to setup work environment
@@ -73,7 +73,7 @@ and run the unit tests again. Find one test failed (red). Now it's time to fix i
 * Implement the function by any way and verify your solution by running tests until the failed test become passed (green).
 * Your solution work, but now time to refactor it. Try to make your code as pretty and simple as possible keeping up the test green.
 * Once you can't improve your code and tests are passed you can commit your solution.
-* Push your updates to github server and check if tests passed on [travis-ci](https://travis-ci.org/rolling-scopes-school/js-assignments/builds).
+* Push your updates to github server and check if tests passed on [travis-ci](https://travis-ci.org/RomanTarasenko/js-assignments/builds).
 * If everything is OK you can try to resolve the next task.
 
 ### How to debug tasks
diff --git a/package.json b/package.json
index 712b264fa..2acdf682b 100644
--- a/package.json
+++ b/package.json
@@ -13,6 +13,6 @@
   },
   "repository" : {
     "type" : "git",
-    "url" : "https://github.com/rolling-scopes-school/js-assignments.git"
+    "url" : "https://github.com/RomanTarasenko/js-assignments.git"
   }
 }