5 - 6 kyu solutions (2021.06.05.)

5 - Directions Reduction.js

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+// https://www.codewars.com/kata/550f22f4d758534c1100025a
+
+function dirReduc(arr){
+    for(let i = 0; i<arr.length; i++){
+      if((arr[i] === 'NORTH' && arr[i+1] === 'SOUTH') || (arr[i] === 'SOUTH' && arr[i+1] === 'NORTH')){
+        arr.splice(i, 2);
+        i=-1;
+      } else if((arr[i] === 'EAST' && arr[i+1] === 'WEST') || (arr[i] === 'WEST' && arr[i+1] === 'EAST')){
+        arr.splice(i, 2);
+        i=-1;
+      }
+    }
+    return arr;
+  }

5 - Formatting a number as price.js

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+//https://www.codewars.com/kata/5318f00b31b30925fd0001f8
+
+const numberToPrice = function(number) {
+    if(isNaN(number)|| number.length <=1){
+      return 'NaN';
+    } else{    
+      let num = String(number).split('.');
+      let fraction ='00';
+      if(num.length===2){
+        fraction = num[1].slice(0,2);
+        if(fraction.length === 1){
+          fraction+='0';
+        }
+      }
+      return `${new Intl.NumberFormat('en-EN',{maximumFractionDigits:0}).format(num[0])}.${fraction}`;
+    }
+  }

5 - Regex Password Validation.js

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+// https://www.codewars.com/kata/52e1476c8147a7547a000811
+
+function validate(password) {
+    return /^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)[A-Za-z\d]{6,}$/.test(password);
+  }

5 - Rot13.js

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+// https://www.codewars.com/kata/530e15517bc88ac656000716
+
+function rot13(message){
+    //a: 97 z:122
+    //return message.split('').map(c => String.fromCharCode(c.charCodeAt(0)+13)).join('');
+
+    const inputTable = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz';
+    const outputTable = 'NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm';
+    let index = x => inputTable.indexOf(x);
+    let shift = x => index(x)> -1 ? outputTable[index(x)] : x;
+    return message.split('').map(shift).join('');
+  }

5 - Where my anagrams at.js

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+// https://www.codewars.com/kata/523a86aa4230ebb5420001e1
+function anagrams(word, words) {
+    return words.filter(element => element.split('').sort().join('') === word.split('').sort().join(''));
+  }

6 - Sum of Digits - Digital Root.js

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+//https://www.codewars.com/kata/541c8630095125aba6000c00
+function digital_root(n) {
+    let result = n.toString().split('').map(x => Number(x)).reduce((a,b)=>a+b);
+    return result<=9 ? result : digital_root(result);
+  }

6 - Turn String Input into Hash.js

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+//https://www.codewars.com/kata/52180ce6f626d55cf8000071
+
+function strToHash(str){
+    let result = {};
+    if(str.length !==0){  
+      let codes = str.split(', ');
+      codes.forEach(
+        element => result[element.substring(0, element.indexOf('='))] = Number(element.substring(element.indexOf('=')+1, element.length))
+      );
+      }
+    return result;
+  }

6 - Are they the same.js

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+// https://www.codewars.com/kata/550498447451fbbd7600041c
+
+function comp(array1, array2){
+    let result = false;
+
+    if(array1 === null || array2 === null){
+      return result;
+    } else if(array1.length !== array2.length){
+      return result;
+    } else if(array1.length === 0 && array2.length === 0){
+      result = true;
+      return result;
+    } else if (Array.isArray(array1) && Array.isArray(array2)){
+      let array1Sorted = array1.map(x => Math.abs(x)).sort((a,b) => a-b);
+      let array2Sorted = array2.sort((a,b) => a-b);
+      for (let i =0; i<array1Sorted.length; i++){
+        if(array1Sorted[i]*array1Sorted[i] === array2Sorted[i]){
+          result = true;
+        } else {
+          result = false;
+          break;
+        }
+      }
+    }
+    return result;
+  }

6 - Bit Counting.js

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+// https://www.codewars.com/kata/526571aae218b8ee490006f4
+
+const countBits = function(n) {
+    return Number(n).toString(2).split('').reduce((x,y) => Number(x)+Number(y), 0);
+  };

6 - Count characters in your string.js

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+//https://www.codewars.com/kata/52efefcbcdf57161d4000091
+
+function count (string) {  
+    let result = {};
+    string.split('').forEach(function(c){
+      result[c] ? result[c]++ : result[c] = 1;
+    });
+    return result;
+  }

6 - Counting Duplicates.js

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+// https://www.codewars.com/kata/54bf1c2cd5b56cc47f0007a1
+
+function duplicateCount(text){
+    let counter = {};
+    text = text.toLowerCase();
+
+    for(let i = 0; i< text.length; i++){
+      counter[text[i]] ? counter[text[i]] += counter[text[i]] : counter[text[i]] = 1;
+    }
+
+    let result = 0;
+    counter = Object.values(counter);
+    for(let i = 0; i < counter.length; i++){
+      if (counter[i] > 1) {
+        result++;
+      }
+    }
+
+    return result;
+  }

6 - Fibonacci, Tribonacci and friends.js

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+// https://www.codewars.com/kata/556e0fccc392c527f20000c5
+
+function Xbonacci(signature,n){
+    const result = signature.slice(0,n);
+    while(result.length < n){
+      result[result.length] = result.slice(-signature.length).reduce((p,c)=>p+c,0);
+    }
+    return result;
+  }

6 - Find the odd int.js

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+//https://www.codewars.com/kata/54da5a58ea159efa38000836
+
+function findOdd(A) {
+    let obj = {};
+    let o = 0;
+    A.map(x => x in obj ? obj[x]+=1 : obj[x] = 1);
+    //console.log(obj);
+    Object.keys(obj).map(x => obj[x]%2!==0 ? o=x : 0)
+    return Number(o);
+  }

6 - Give me a Diamond.js

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+//https://www.codewars.com/kata/5503013e34137eeeaa001648
+
+function diamond(n){
+    if(n < 0 || !(n%2)){
+      return null;
+    }
+
+    const middleIdx = Math.floor(n/2);
+    //Array.apply: The apply() method calls a function with a given this value, 
+    //and arguments provided as an array (or an array-like object).
+    return Array.apply(null, {length: n})
+      .map((element, index) => {
+        const indent = Math.abs(index-middleIdx);
+        const numOfStars = n - indent*2;
+        return Array(indent + 1).join(' ') + Array(numOfStars + 1).join('*');
+    }).join('\n')+'\n';  
+  }

6 - Help the bookseller.js

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+// https://www.codewars.com/kata/54dc6f5a224c26032800005c
+
+function stockList(listOfArt, listOfCat){
+    let result = {};
+    for(let i = 0; i<listOfCat.length; i++){
+      result[listOfCat[i]] = 0;
+    }
+
+    if(listOfArt.length === 0 || listOfCat === 0){
+      return '';
+    } else {
+      let catalog = listOfArt.reduce(function(acc, curr, i){
+        i = curr.substring(0, curr.indexOf(' '));
+        curr = curr.substring(curr.indexOf(' ')+1);
+        acc[i] = curr;
+        return acc;
+      }, {});
+      console.log('Categories: ', listOfCat);
+
+      let catalogKeys = Object.keys(catalog).map(x => x[0]);
+      let catalogValues = Object.values(catalog);
+
+      for(let i = 0; i < listOfCat.length; i++){
+        for(let j = 0; j<catalogKeys.length; j++){
+          if(catalogKeys[j] === listOfCat[i]){
+            result[listOfCat[i]] = Number(result[listOfCat[i]]) + Number(catalogValues[j]);
+          }
+        }      
+      } 
+
+      let renderResult = res =>{
+        return Object.keys(res).map(k => `(${k} : ${res[k]})`).join(' - ');
+      }
+
+      return renderResult(result);    
+    }
+  }

6 - IQ Test.js

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+//https://www.codewars.com/kata/552c028c030765286c00007d
+
+// Bob is preparing to pass IQ test. The most frequent task in this test is to find out which one of the given numbers differs from the others. Bob observed that one number usually differs from the others in evenness. Help Bob — to check his answers, he needs a program that among the given numbers finds one that is different in evenness, and return a position of this number.
+
+// ! Keep in mind that your task is to help Bob solve a real IQ test, which means indexes of the elements start from 1 (not 0)
+
+// Examples:
+// iqTest("2 4 7 8 10") => 3 // Third number is odd, while the rest of the numbers are even
+
+// iqTest("1 2 1 1") => 2 // Second number is even, while the rest of the numbers are odd
+
+
+function iqTest(numbers){
+    const numberArr = numbers.split(' ').map(num => Number(num));
+    const even = numberArr.filter(num => num%2 === 0);
+    const odd = numberArr.filter(num => num%2 !==0);
+    return odd.length < even.length ? numberArr.indexOf(odd[0])+1 : numberArr.indexOf(even[0])+1;
+  }

6 - If you can read this.js

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+// https://www.codewars.com/kata/586538146b56991861000293
+
+function to_nato(words) {
+    let result = '';
+
+    for(const char of words){
+      let c = char.toLowerCase()
+      if (Object.keys(NATO).includes(c)){
+        result += NATO[c] + ' ';
+      } else if(c === ',' || c === '.' || c === '!' || c === '?'){
+        result += c + ' ';
+      } 
+    }
+
+    return result.slice(0, result.length-1);
+  }

6 - Longest alphabetical substring.js

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+//https://www.codewars.com/kata/5a7f58c00025e917f30000f1
+
+function longest(str) {
+    let longest = '',
+        length = 0,
+        start = 0,
+        prev = str[0];
+
+    for(let i = 1; i <= str.length; ++i){
+      if(i === str.length || str[i] < prev){
+        if(length < i-start){
+          longest = str.substring(start, i);
+          length = i-start;
+        }
+        start = i;
+      }
+      prev = str[i];
+    };
+
+    return longest;
+  }

6 - Mexican Wave.js

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+// https://www.codewars.com/kata/58f5c63f1e26ecda7e000029
+
+function wave(str){
+    const result = [];
+    for (let i = 0; i < str.length; i++){
+      if(str[i] !== ' ') {
+        result.push(Array.from(str, (c, j) => i === j ? c.toUpperCase() : c).join(''));
+      }
+    }
+    return result;
+  }

6 - Moves in squared strings (II).js

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+//https://www.codewars.com/kata/56dbe7f113c2f63570000b86
+
+function rot(strng) {
+    return strng.split('\n').map(x => x.split('').reverse().join('')).reverse().join('\n');
+}
+function selfieAndRot(strng) {
+    return strng.split('\n').map(x=> x + '.'.repeat(x.length)).join('\n')+'\n'+
+      strng.split('\n').map(x=> x + '.'.repeat(x.length)).reverse().map(x=>x.split('').reverse().join('')).join('\n');
+}
+function oper(fct, s) {
+    return fct(s);
+}

6 - One line task Square Every Digit.js

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+// https://www.codewars.com/kata/5acd142a2ec8c48521000104
+sd=x=>+[...x+''].map(d=>d*d).join``

6 - Parse HTML-CSS Colors.js

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+// https://www.codewars.com/kata/58b57ae2724e3c63df000006
+
+function parseHTMLColor(color) {
+    //transform color to lowercase
+    let tempColor = color.toLowerCase();
+
+    //named color to 6digit hex
+    if(Object.keys(PRESET_COLORS).includes(tempColor)){
+      tempColor = PRESET_COLORS[tempColor];
+    }
+
+    //remove #
+    tempColor = tempColor.substring(1).split('');
+
+    //3digit hex to 5digit hex
+    if(tempColor.length === 3){
+      tempColor = tempColor.reduce((c,i)=>c.concat(i,i),[]);
+    }
+
+    //from array format to string
+    tempColor = tempColor.join('');
+
+    //calculate rgb
+    let result = {
+      r: parseInt(tempColor.slice(0,2),16),
+      g: parseInt(tempColor.slice(2,4),16),
+      b: parseInt(tempColor.slice(4,6),16)
+    }
+
+    return result;  
+  }

6 - Replace With Alphabet Position.js

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+// https://www.codewars.com/kata/546f922b54af40e1e90001da
+
+function alphabetPosition(text) {
+    //ASCII a --> 97
+    //ASCII z --> 122
+    const compensateAscii = 96;
+    let result = '';
+
+    for (let i = 0; i<text.length; i++){
+      let code = text.toLowerCase().charCodeAt(i);
+      if (code > 96 && code < 123){
+        result += (code-compensateAscii) + ' ';
+      }
+    }
+
+    return result.slice(0, result.length-1);
+  }