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PHP quick sort algorithm

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Release： 2016-07-25 08:43:06
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  1. function qsort(&$arr)
  2. {
  3. _quick_sort($arr, 0, count($arr) - 1);
  4. }
  6. /**
  7. * Quick sort using recursive algorithm.
  8. *
  9. * @param array $arr The array to be sorted
  10. * @param int $low The lowest sorted subsection
  11. * @param int $high The highest sorted field
  12. */
  13. function _quick_sort(&$arr, $low, $high)
  14. {
  15. $low_data = $arr[$low];
  16. $prev_low = $low;
  17. $prev_high = $high;
  18. while ($low < $high)
  19. {
  20. while ($arr[$high] >= $low_data && $low < $high) {
  21. $high--;
  22. }
  23. if ($low < $high) {
  24. $arr[$low] = $arr[$high];
  25. $low++;
  26. }
  27. while ($arr[$low] <= $low_data && $low < $high) {
  28. $low++;
  29. }
  30. if ($low < $high) {
  31. $arr[$high] = $arr[$low];
  32. $high--;
  33. }
  34. }
  35. $arr[$low] = $low_data;
  36. if ($prev_low < $low) {
  37. _quick_sort($arr, $prev_low, $low);
  38. }
  39. if ($low + 1 < $prev_high) {
  40. _quick_sort($arr, $low + 1, $prev_high);
  41. }
  42. }
  44. function quick_sort(&$arr)
  45. {
  46. $stack = array();
  47. array_push($stack, 0);
  48. array_push($stack, count($arr) -1);
  49. while (!empty($stack)) {
  50. $high = array_pop($stack);
  51. $low = array_pop($stack);
  52. $low_data = $arr[$low];
  53. $prev_low = $low;
  54. $prev_high = $high;
  55. while ($low < $high)
  56. {
  57. while ($arr[$high] >= $low_data && $low < $high) {
  58. $high--;
  59. }
  60. if ($low < $high) {
  61. $arr[$low] = $arr[$high];
  62. $low++;
  63. }
  64. while ($arr[$low] <= $low_data && $low < $high) {
  65. $low++;
  66. }
  67. if ($low < $high) {
  68. $arr[$high] = $arr[$low];
  69. $high--;
  70. }
  71. }
  72. $arr[$low] = $low_data;
  73. if ($prev_low < $low) {
  74. array_push($stack, $prev_low);
  75. array_push($stack, $low);
  76. }
  77. if ($low + 1 < $prev_high) {
  78. array_push($stack, $low + 1);
  79. array_push($stack, $prev_high);
  80. }
  81. }
  82. }
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php快速排序的算法
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