1. let countSort = arr =>{
    2.     let hashTable = {}, max = 0, result = []
    3.     for(let i=0; i<arr.length; i++){ 
    4.         if(!(arr[i] in hashTable)){
    5.             hashTable[arr[i]] = 1
    6.         }else{
    7.             hashTable[arr[i]] += 1
    8.         }
    9.         if(arr[i] > max) {max = arr[i]}
    10. }
    11. for(let j=0; j<=max; j++){ 
    12.     if(j in hashTable){
    13.       for(let i = 0; i<hashTable[j]; i++){
    14.         result.push(j)
    15.    }
    16.     }
    17. }
    18.     return result
    19. }
    1. let mergeSort = arr =>{
    2.     let k = arr.length
    3.     if(k===1){return arr}
    4.     let left = arr.slice(0, Math.floor(k/2))
    5.     let right = arr.slice(Math.floor(k/2))
    6.     return merge(mergeSort(left), mergeSort(right))
    7. }
    8. let merge = (a, b)=>{
    9.     if(a.length === 0) return b
    10.     if(b.length === 0) return a
    11.     return a[0] > b[0] ?
    12.         [b[0]].concat(merge(a, b.slice(1))) :
    13.         [a[0]].concat(merge(a.slice(1), b))
    14. }
    1. let quickSort = arr => {
    2.     if (arr.length <= 1) { return arr; }
    3.     let pivotIndex = Math.floor(arr.length / 2);
    4.     let pivot = arr.splice(pivotIndex, 1)[0];
    5.     let left = [];
    6.     let right = [];
    7.     for (let i = 0; i < arr.length; i++){
    8.         if (arr[i] < pivot) { left.push(arr[i])
    9.         } else { right.push(arr[i]) }
    10.     }
    11.     return quickSort(left).concat(
    12.             [pivot], quickSort(right) )
    13. }