php经典算法集锦

for ($i = 1; ; $i++){  if ($i%5 == 1) {    //第一个人取五分之一，还剩$t    $t = $i - round($i/5) - 1;    if($t % 5 == 1)    {      //第二个人取五分之一，还剩$r      $r = $t - round($t/5) - 1;      if($r % 5 == 1)      {        //第三个人取五分之一，还剩$s        $s = $r - round($r/5) - 1;        if($s % 5 == 1)        {          //第四个人取五分之一，还剩$x          $x = $s - round($s/5) - 1;          if($x % 5 == 1)          {            //第五个人取五分之一，还剩$y            $y = $x - round($x/5) - 1;            if ($y % 5 == 1) {              echo $i;              break;            }          }        }      }    }  }}

function king($n, $m){  $monkeys = range(1, $n);  $i=0;  $k=$n;  while (count($monkeys)>1) {    if(($i+1)%$m==0) {      unset($monkeys[$i]);    } else {      array_push($monkeys,$monkeys[$i]);      unset($monkeys[$i]);    }    $i++;  }  return current($monkeys);}$a = king(5, 2);var_dump($a);

function hanoi($n,$x,$y,$z){  if($n==1){    echo 'move disk 1 from '.$x.' to '.$z."/n";  }else{    hanoi($n-1,$x,$z,$y);    echo 'move disk '.$n.' from '.$x.' to '.$z."/n";    hanoi($n-1,$y,$x,$z);  }   }hanoi(3,'A','B','C');

//对数组冒泡排序function bubble_sort($array){  $count = count($array);  if ($count <= 0)     return false;    for($i=0; $i<$count; $i++){      for($j=$count-1; $j>$i; $j){      if ($array[$j] < $array[$j-1]){        $tmp = $array[$j];        $array[$j] = $array[$j-1];        $array[$j-1] = $tmp;    }  }}return $array;}function quick_sort($array) {  if (count($array) <= 1) return $array;  $key = $array[0];  $left_arr = array();  $right_arr = array();  for ($i=1; $i<count($array); $i++){  if ($array[$i] <= $key)    $left_arr[] = $array[$i];  else    $right_arr[] = $array[$i];  }  $left_arr = quick_sort($left_arr);  $right_arr = quick_sort($right_arr);  return array_merge($left_arr, array($key), $right_arr);}

//使用二分查找数组中某个元素function bin_sch($array, $low, $high, $k){  if ($low <= $high){    $mid = intval(($low+$high)/2);    if ($array[$mid] == $k){      return $mid;    }elseif ($k < $array[$mid]){    return bin_sch($array, $low, $mid-1, $k);  }else{    return bin_sch($array, $mid+1, $high, $k);  }  }  return -1;}

function array_sort($arr, $keys, $order=0) {  if (!is_array($arr)) {    return false;  }  $keysvalue = array();  foreach($arr as $key => $val) {    $keysvalue[$key] = $val[$keys];  }  if($order == 0){    asort($keysvalue);  }else {    arsort($keysvalue);  }  reset($keysvalue);  foreach($keysvalue as $key => $vals) {    $keysort[$key] = $key;  }  $new_array = array();  foreach($keysort as $key => $val) {    $new_array[$key] = $arr[$val];  }  return $new_array;}