标签：style blog http io color ar sp for div
Red is current min. Yellow is sorted list. Blue is current item. (picture from wikipedia, a little too fast)
10 numbers. Sort as ascend.
1. Find the min of the 10 and switch it with a[0], requires 9 times of compare
2. Find the min of the rest 9 and switch it with a[1], requires 8 times of compare
. . .
1, 10, 9
2, 9, 8
3, 8, 7
4, 7, 6
5, 6, 5
6, 5, 4
7, 4, 3
8, 3, 2
9, 2, 1
In conclusion: For 10 numbers, we need 9 times of finding the min, each has one-short amount of numbers to compare.
Implementation in PHP:
1 <?php 2 /* selection sort: 3 1. operate directly on the input array (&), not on a copy 4 2. sort as ascend 5 6 a is array 7 m is length of a 8 n is times of outer loop, which is finding min of the rest 9 i/j is for-loop counter 10 w is for value swap 11 min is min 12 sub is index of array 13 */ 14 function sortSelection(&$a){ 15 $m = count($a); 16 $n = $m - 1; 17 $min; 18 $sub; 19 for($i=0; $i<$n; $i++){ 20 $min = $a[$i]; 21 $sub = $i; 22 for($j=$i; $j<$m; $j++){ 23 if($a[$j] < $min){ 24 $min = $a[$j]; 25 $sub = $j; 26 } 27 else{ 28 // 29 } 30 } 31 $a[$sub] = $a[$i]; 32 $a[$i] = $min; 33 // echo implode(‘, ‘, $a).‘<br />‘; 34 } 35 } 36 37 $arr = array(9, 5, 2, 7, 3, 1, 6, 4, 0, 8); 38 sortSelection($arr); 39 echo implode(‘, ‘, $arr); 40 41 // 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 42 ?>
标签：style blog http io color ar sp for div
原文地址：http://www.cnblogs.com/crepesofwrath/p/4085287.html
