JS實現快速排序（2種方法）
阿新 • • 發佈：2019-02-10
1、用i和j兩個指標
2、用一個指標判斷，大的放在右邊，小的數放在左邊
<!DOCTYPE html> <html> <head> <title>quickSort</title> <meta charset="utf-8"/> <script type="text/javascript"> var arr=[12,20,5,16,15,1,30,45,23,9]; var start = 0; var end = arr.length; console.log('arr:' +arr); function quickSort(arr,low,high){ var key=arr[low]; var start=low; var end=high; while(end>start){ while(end>start&&arr[end]>=key) end--; if(arr[end]<=key){ var temp = arr[end]; arr[end]=arr[start]; arr[start] = temp; } while(end>start&&arr[start]<=key) start++; if(arr[start]>=key){ var temp = arr[start]; arr[start]=arr[end]; arr[end]=temp; } } if(start>low) quickSort(arr,low,start-1); if(end<high) quickSort(arr,end+1,high); } quickSort(arr,start,end); console.log('After arr:' +arr); </script> <script type="text/javascript"> function sort(elements){ if(elements.length<=1){ return elements; } var piIndex = Math.floor(elements.length/2);//取陣列中間值 console.log(piIndex); var pi = elements.splice(piIndex,1)[0];//???在中間值的地方插入元素 var left = []; var right = []; for(var i =0;i<elements.length;i++){ if(elements[i]<pi){ left.push(elements[i]); } else { right.push(elements[i]); } } return sort(left).concat([pi],sort(right)); } var elements=[12,20,5,16,15,1,30,45,23,9]; document.write(sort(elements)); </script> </head> <body> </body> </html>