JavaScript Algorithms

freecodecamp-basic-algorithm.js

function reverseString(str) {
  splitted = str.split("");
  reversed = splitted.reverse();
  joined = reversed.join("");
  return joined;
}

reverseString("hello");

function factorialize(num) {
  if( num == 0 ) return 1;
  return num * factorialize(num - 1);
}

factorialize(5);


function palindrome(str) {
  // Good luck!
  str0 = str.replace(/[\W_]/g, '');
  str1 = str0.toLowerCase();
  str2 = str1.split("");  
  str3 = str2.reverse();
  str4 = str3.join("");
  
  if( str1 === str4 ){
    return true;
  } else{
    return false;
  }
}

palindrome("eye");


function findLongestWord(str) {
  array = str.split(" ");
  var length = 0;
  array.map(function(val){
    if(val.length > length){
     length = val.length;
    }
  });
  
  return length;
}

findLongestWord("The quick brown fox jumped over the lazy dog");

function titleCase(str) {
  splitted = str.toLowerCase().split(" ");
  var lowercased = splitted.map(function(value){
    return value.replace(value.charAt(0), value.charAt(0).toUpperCase());
  });
    
  joined = lowercased.join(" ");
  return joined;
}

titleCase("I'm a little tea pot");


function largestOfFour(arr) {
  // You can do this!
      var final = [ ];
  for(i = 0; i < arr.length; i++){
    var largeNum = 0;
    for(j=0; j < arr[i].length; j++){
      if(arr[i][j] > largeNum){
        largeNum = arr[i][j]; 
      }
    }
    
    final.push(largeNum);
   }
  return final;
}

largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]]);


function confirmEnding(str, target) {
  // "Never give up and good luck will find you."
  // -- Falcor
  stringlength = str.length;
  string = str.substr(stringlength-target.length, target.length);
  
  if(string == target){
    return true;
  } else{
    return false;
  }
  
}

confirmEnding("Bastian", "n");


function repeatStringNumTimes(str, num) {
  // repeat after me
  if(num > 0 ){
    str1 = "";
    for(i=0; i < num; i++){
      str1 += str;
    }
    return str1;
    
  } else {
    return "";
  }
}

repeatStringNumTimes("abc", 3);


function truncateString(str, num) {
  // Clear out that junk in your trunk
  if(str.length > num && num > 3){
    reduced = str.slice(0, num-3) + "...";
  } else if(str.length > num && num <= 3) {
    reduced = str.slice(0, num) + "...";
  } else{
    reduced = str;
  }
 
  return reduced;
}

truncateString("A-tisket a-tasket A green and yellow basket", 11);


function chunkArrayInGroups(arr, size) {
  // Break it up.
  var newArray = [];
  
  for(i = 0; i < arr.length; i+=size){
    var items = arr.slice(i, i+size);
    newArray.push(items);
  }
  
  return newArray;
}

chunkArrayInGroups(["a", "b", "c", "d"], 2);


function slasher(arr, howMany) {
  // it doesn't always pay to be first
  return arr.splice(howMany, arr.length-howMany);
}

slasher([1, 2, 3], 2);


function mutation(arr) {
  var lowercased1 = arr[1].toLowerCase();
  var lowercased0 = arr[0].toLowerCase();

  for(i=0; i < lowercased1.length; i++){
  if (lowercased0.indexOf(lowercased1[i]) === -1){
      return false;
    } 
  }

  return true;
}

mutation(["hello", "hey"]);


function bouncer(arr) {
  return arr.filter(function(value){
    if (value){
      return (value);
    }
  });
}

bouncer([7, "ate", "", false, 9]);

function destroyer(arr) {
  var args = Array.prototype.slice.call(arguments);

  for (var i = 0; i < arr.length; i++) {
    for (var j = 0; j < args.length; j++) {
      if (arr[i] === args[j]) {
        delete arr[i];
      }
    }
  }
  return arr.filter(Boolean);
}

destroyer([1, 2, 3, 1, 2, 3], 2, 3);


function getIndexToIns(arr, num) {
  // Find my place in this sorted array.
  sortedArray = arr.sort(function(a, b){return a-b});
  sortedArray.push(num);
  
  sortedArray = sortedArray.sort(function(a, b){return a-b});
  
  position = sortedArray.indexOf(num);
  
  return position;
}

getIndexToIns([40, 60], 50);


function rot13(str) { // LBH QVQ VG!
  
  array = str.split("");
  
  return array.map(function(value){
      x = value.charCodeAt(0);
      // Checks if character lies between A-Z
      if (x < 65 || x > 90) {
        return String.fromCharCode(x);  // Return un-converted character
      }
      //N = ASCII 78, if the character code is less than 78, shift forward 13 places
      else if (x < 78) {
        return String.fromCharCode(x + 13);
      }
    
      return String.fromCharCode(x - 13);
  }).join("");
}

// Change the inputs below to test
rot13("SERR PBQR PNZC");