归纳公式

选择排序 - 图1
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转公式为代码

https://jsbin.com/jayojekabe/2/edit?js,console

  1. const swap = (a, i, j) => [a[i], a[j]] = [a[j], a[i]];
  3. const _sortSelect = (a, start) => {
  4.   if (start >= a.length - 1) return a;
  5.   let min = a[start];
  6.   let minIndex = start;
  7.     for(let i = start + 1; i < a.length; i++) {
  8.       if (a[i] < min) {
  9.         min = a[i];
  10.         minIndex = i;
  11.     }
  12.   }
  13.   if (minIndex !== start) {
  14.       swap(a, start, minIndex);
  15.   }
  16.   return _sortSelect(a, start + 1);
  17. }
  18. const sortSelect = (a) => _sortSelect(a, 0);
  20. console.log('------------', sortSelect([2, 1, 3, 1, 4]))
  22. console.log('--------', sortSelect([1,2,9,4,10,20,12]))
  23. // // [1, 2, 4, 9, 10, 12, 20]
  24. console.log('--------', sortSelect([11,2,39,24,1,2,9]))
  25. // //  [1, 2, 2, 9, 11, 24, 39]
  26. console.log('--------', sortSelect([]))
  28. // // []
  29. console.log('--------', sortSelect([1,1,1,1,1]))
  32. const sortSelect2 = (a) => {
  33.     for(let i = 0; i < a.length; i++) {
  34.     let min = a[i];
  35.       let minIndex = i;
  36.     for(let j = i + 1; j < a.length; j ++) {
  37.         if (a[j] < min) {
  38.             min = a[j];
  39.             minIndex = j;
  40.            }
  41.     }
  42.       swap(a, i, minIndex);
  43.   }
  44.   return a;
  45. }
  47. console.log('------------', sortSelect2([2, 1, 3, 1, 4]))
  49. console.log('--------', sortSelect2([1,2,9,4,10,20,12]))
  50. // // // [1, 2, 4, 9, 10, 12, 20]
  51. console.log('--------', sortSelect2([11,2,39,24,1,2,9]))
  52. // // //  [1, 2, 2, 9, 11, 24, 39]
  53. console.log('--------', sortSelect2([]))
  55. // // // []
  56. console.log('--------', sortSelect2([1,1,1,1,1]))