8. The Sorting Algorithm summarizes JS implementation, and the algorithm js
// Bubble sort
function bubbleSort(arr,comp){for(var i = 0;i < arr.length; i++){for(var j = 0; j < arr.length - i - 1; j++){if(comp(arr[j],arr[j+1])){exch(arr,j,j+1);}}}}function exch(a,i,j){var tmp = a[i];a[i] = a[j];a[j] = tmp;}var input = new Array(5,1,4,2,3);bubbleSort(input,function(a,b){return a > b;});console.log(input);input = new Array(5,1,4,2,3);bubbleSort(input,function(a,b){return a < b;});console.log(input);
// Selection sort
function selectionSort(arr,comp){for(var i = 0;i < arr.length ; i++){for(var j = i;j < arr.length ; j++){if(comp(arr[i],arr[j])) { exch(arr,i,j); }}}}function exch(a,i,j){var t = a[i];a[i] = a[j];a[j] = t;}var input = new Array(5,1,4,2,3);selectionSort(input,function(a,b){return a > b;});console.log(input);input = new Array(5,1,4,2,3);bubbleSort(input,function(a,b){return a < b;});console.log(input);
// Insert sort
function insertSort(arr,comp){var result = new Array();for(;arr.length > 0;){var inserted = false;for(var j = 0;j < result.length; j++){if(comp(result[j],arr[0])) { insert(result,j,arr[0]); inserted = true; break;}}if(!inserted){insert(result,result.length,arr[0]);}arr.splice(0,1);}return result;}function insert(arr,i,v){arr.splice(i,0,v);}var input = new Array(5,1,4,2,3);var ret = insertSort(input,function(a,b){return a > b;});console.log(ret);var input = new Array(5,1,4,2,3);ret = insertSort(input,function(a,b){return a < b;});console.log(ret);
// Shell sort
function shellSort (a,comp) { for (var h = a.length; h = parseInt(h / 2);) { for (var i = h; i < a.length; i++) { var k = a[i]; for (var j = i; j >= h && comp(k, a[j - h]); j -= h) a[j] = a[j - h]; a[j] = k; } } return a;}var arr =new Array(7,9,2,5,4,1,3);var r = shellSort(arr,function (a,b){return a > b;});console.log(r);
// Merge sort
function mergeS(arr,comp){if(arr.length == 1){return arr;}var mid = arr.length / 2 | 0;var leftArr = new Array();var rightArr = new Array();for(var i = 0;i < mid;i ++){leftArr.push(arr[i]);}for(var j = mid;j < arr.length; j++){rightArr.push(arr[j]);}console.log("before : " + leftArr + " | " + rightArr);var leftRet = mergeS(leftArr,comp);var rightRet = mergeS(rightArr,comp);var r = merge(leftRet,rightRet,comp);return r;}function merge(leftArr,rightArr,comp){var ret = new Array();var i = j = 0;for(;i < leftArr.length && j < rightArr.length; ){if(comp(leftArr[i],rightArr[j])){ret.push(leftArr[i]); i ++}else {ret.push(rightArr[j]); j ++}}for(;i < leftArr.length;){ret.push(leftArr[i]);i++;}for(;j< rightArr.length; ){ret.push(rightArr[j]);j++;}return ret;}var r = mergeS(new Array(0,6,5,1,2,4,3,9),function(a,b){return a > b;});console.log(r);
// Quick sort
function quickS(arr,lo,hi,comp){if(lo >= hi){return ;}var stub = arr[lo];var i = lo + 1;var j = hi;for(;i < j ;){for(;i < j && !comp(stub,arr[j]);j--);for(;i < j && comp(stub,arr[i]);i++);if(i >= j){break;}var t = arr[i];arr[i] = arr[j];arr[j] = t;j--;i++;}if(comp(arr[lo],arr[i])){var t = arr[lo];arr[lo] = arr[i];arr[i] = t;}quickS(arr,lo,i-1,comp);quickS(arr,i,hi,comp);}var input = new Array(22,3,10,66,15,11,2,4,31,9);quickS(input, 0, input.length - 1,function(a,b){return a > b;});console.log(input);
// Heap sort
var ret = new Array();function heapS(arr,comp){if(arr.length == 0){return ;}var i = arr.length / 2 | 0 ;for(;i >= 0; i--){if(comp(arr[i], arr[i * 2])){exch(arr, i, i*2);}if(comp(arr[i], arr[i * 2 + 1])) {exch(arr, i, i*2 + 1);}}ret.push(arr[0]);arr.splice(0,1);heapS(arr,comp);}function exch(arr,i,j){var t = arr[i];arr[i] = arr[j];arr[j] = t;}heapS(new Array(16,22,91,0,51,44,23),function (a,b){return a > b;});console.log(ret);