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快速排序QuickSort算法JavaScript实现, 包括 Hoare 和 Lomuto 版本的实现，以及网友实现版本的对比
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| <html> | |
| <body> | |
| <script> | |
| // @author: ideawu | |
| // @link: http://www.ideawu.net/blog/archives/1021.html | |
| var swap_count = 0; | |
| var cmp_count = 0; | |
| // https://gist.github.com/wintercn/c30464ed3732ee839c3eeed316d73253 | |
| function wintercn_qsort(arr, start, end){ | |
| var midValue = arr[start]; | |
| var p1 = start, p2 = end; | |
| while(p1 < p2) { | |
| swap(arr, p1, p1 + 1); | |
| while(compare(arr[p1], midValue) >= 0 && p1 < p2) { | |
| swap(arr, p1, p2--); | |
| } | |
| p1 ++; | |
| } | |
| if(start < p1 - 1) | |
| wintercn_qsort(arr, start, p1 - 1); | |
| if(p1 < end) | |
| wintercn_qsort(arr, p1, end); | |
| } | |
| // http://www.ruanyifeng.com/blog/2011/04/quicksort_in_javascript.html | |
| var ruanyifeng_qsort = function(arr) { | |
| if (arr.length <= 1) { return arr; } | |
| var pivotIndex = Math.floor(arr.length / 2); | |
| var pivot = arr.splice(pivotIndex, 1)[0]; | |
| swap_count++; | |
| var left = []; | |
| var right = []; | |
| for (var i = 0; i < arr.length; i++){ | |
| if (compare(arr[i], pivot) < 0) { | |
| swap_count++; | |
| left.push(arr[i]); | |
| } else { | |
| swap_count++; | |
| right.push(arr[i]); | |
| } | |
| } | |
| swap_count++; | |
| return ruanyifeng_qsort(left).concat([pivot], ruanyifeng_qsort(right)); | |
| } | |
| function compare(a, b){ | |
| cmp_count ++; | |
| return a-b; | |
| } | |
| function swap(arr, s, e){ | |
| swap_count ++; | |
| var tmp = arr[s]; | |
| arr[s] = arr[e]; | |
| arr[e] = tmp; | |
| } | |
| function partition_hoare(arr, start, end){ | |
| var pivot = arr[start]; | |
| var s = start; | |
| var e = end; | |
| while(1){ | |
| while(compare(arr[s], pivot) < 0){ | |
| s ++; | |
| } | |
| while(compare(arr[e], pivot) > 0){ | |
| e --; | |
| } | |
| if(s == e){ | |
| return s; | |
| }else if(s > e){ | |
| return s-1; | |
| } | |
| swap(arr, s, e); | |
| s++; | |
| e--; | |
| } | |
| } | |
| function qsort_hoare(arr, start, end){ | |
| if(start >= end){ | |
| return; | |
| } | |
| var p = partition_hoare(arr, start, end); | |
| qsort_hoare(arr, start, p); | |
| qsort_hoare(arr, p+1, end); | |
| } | |
| function partition_lomuto(arr, start, end){ | |
| var pivot = arr[end]; | |
| var s = start; | |
| for(var g = start; g < end; g++){ | |
| if(compare(arr[g], pivot) < 0){ | |
| if(s != g){ | |
| swap(arr, s, g); | |
| } | |
| s ++; | |
| } | |
| } | |
| if(s == end){ | |
| return s-1; | |
| }else{ | |
| swap(arr, s, end); | |
| return s; | |
| } | |
| } | |
| function qsort_lomuto(arr, start, end){ | |
| if(start >= end){ | |
| return; | |
| } | |
| // console.log('in', arr, start, end); | |
| var p = partition_lomuto(arr, start, end); | |
| // console.log(JSON.stringify(arr.slice(start, p+1)), JSON.stringify(arr.slice(p+1, end+1))); | |
| qsort_lomuto(arr, start, p); | |
| qsort_lomuto(arr, p+1, end); | |
| } | |
| function bubble_sort(arr, start, end){ | |
| for(var i=start; i<=end; i++){ | |
| for(var j=start; j<=end-i-1; j++){ | |
| if(compare(arr[j], arr[j+1]) > 0){ | |
| swap(arr, j, j+1); | |
| } | |
| } | |
| } | |
| } | |
| function check_result(a){ | |
| var pass = true; | |
| var v = a[0]; | |
| for(var j=0; j<a.length; j++){ | |
| var n = a[j]; | |
| if(n < v){ | |
| pass = false; | |
| break; | |
| } | |
| v = a[j]; | |
| } | |
| return pass; | |
| } | |
| function run_test(func, name){ | |
| document.write('<b>run test: ', name, '</b><br/>'); | |
| swap_count = 0; | |
| cmp_count = 0; | |
| var nlogn = 0; | |
| var stime = (new Date()).getTime(); | |
| for(var i=1; i<=arr.length; i++){ | |
| var a = arr.slice(0, i); | |
| var b = func(a, 0, a.length - 1); | |
| if(func == ruanyifeng_qsort){ | |
| a = b; | |
| } | |
| if(!check_result(a)){ | |
| console.log(i, 'fail'); | |
| console.log(a); | |
| } | |
| nlogn += Math.floor(i*Math.log(i)); | |
| // console.log('n:', i, 'swaps:', swap_count, 'compares:', cmp_count, 'nlogn:', Math.floor(i*Math.log(i)), JSON.stringify(a)); | |
| } | |
| var etime = (new Date()).getTime(); | |
| document.write('time: ', etime-stime, ' ms', '<br/>'); | |
| document.write('compare: ', cmp_count, ' swap: ', swap_count, ' nlogn: ', nlogn, '<br/>'); | |
| document.write('<br/>'); | |
| } | |
| var count = 2000; | |
| var arr = []; | |
| for(var i=0; i<count; i++){ | |
| arr.push(Math.floor(Math.random() * count)); | |
| } | |
| console.log('datasource:', JSON.stringify(arr)); | |
| document.write('Running...'); | |
| setTimeout(function(){ | |
| document.write('<pre>'); | |
| run_test(wintercn_qsort, 'wintercn_qsort'); | |
| run_test(ruanyifeng_qsort, 'ruanyifeng_qsort'); | |
| run_test(qsort_hoare, 'qsort_hoare'); | |
| run_test(qsort_lomuto, 'qsort_lomuto'); | |
| document.write('</pre>'); | |
| // document.write('Running bubble_sort...'); | |
| // setTimeout(function(){ | |
| // document.write('<pre>'); | |
| // run_test(bubble_sort, 'bubble_sort'); | |
| // document.write('</pre>'); | |
| // }, 0); | |
| }, 0); | |
| </script> | |
| </body> | |
| </html> |
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