Question

所以这里的答案适用于C，但我试图用PHP，以特定的方式做到这一点。

我有一系列这样的数字：

7,2,6,3,10

我想找到按给定顺序首先发生的增长最长的子序列。因此，例如在这种情况下，我希望结果为：

2,6,10

而不是2,3,10。

实现这一目标的最佳方法是什么？

Answer 1

好的，这是你的问题的解决方案，产生你期望的答案。基本上，对于找到的每个元素，当它们大于列表中的最后一个项目时，它会启动一个列表并添加项目。

$input = array(7,2,6,3,10);
$trial = array();

echo "Input: ";
print_r($input);
echo "<br><br>\n";

foreach ($input as $key => $value)
{
  // Create a new trial for each starting point
  // ------------------------------------------
  $trial[$key][0] = $value;
  echo "Trial $key started<br>\n";

  // Process all prior trials
  // ------------------------
  for ($i = $key-1; $i >= 0; $i--)
  {
    echo "Looking at trial $i ";
    $last = count($trial[$i]) - 1;
    $lastval = $trial[$i][$last];
    if ( $value > $lastval )
    {
      $trial[$i][] = $value;
      echo "** added $value";
    }
    echo "<br>\n";
  }
  echo "<br>\n";
}

// Find first longest trial
// ------------------------
$longest = 0;
foreach ($trial as $key => $list)
{
  if ( count($list) > count($trial[$longest]) )
    $longest = $key;
}

echo "All trials:<br>\n";
print_r($trial);
echo "<br><br>\n";

echo "First longest sequence:<br>\n";
print_r($trial[$longest]);

如果您拥有非常大的数据集，当然可以采用不同的方式。也就是说，这里有一些“调试”输出显示它的实际效果：

Input: Array ( [0] => 7 [1] => 2 [2] => 6 [3] => 3 [4] => 10 ) 

Trial 0 started

Trial 1 started
... looking at trial 0 

Trial 2 started
... looking at trial 1 ** added 6
... looking at trial 0 

Trial 3 started
... looking at trial 2 
... looking at trial 1 
... looking at trial 0 

Trial 4 started
... looking at trial 3 ** added 10
... looking at trial 2 ** added 10
... looking at trial 1 ** added 10
... looking at trial 0 ** added 10

All trials:
Array ( 
  [0] => Array ( [0] => 7 [1] => 10 ) 
  [1] => Array ( [0] => 2 [1] => 6 [2] => 10 ) 
  [2] => Array ( [0] => 6 [1] => 10 ) 
  [3] => Array ( [0] => 3 [1] => 10 ) 
  [4] => Array ( [0] => 10 ) 
) 

First longest sequence:
Array ( [0] => 2 [1] => 6 [2] => 10 )

Answer 2

试试此代码

<?php

$data = array(7, 2, 6, 3, 10);
$slice_array=array_slice($data,array_search(min($data),$data));
$result=array();

for($i=array_search(min($slice_array),$slice_array);$i<=array_search(max($slice_array),$slice_array);$i++){
     if(end($result)<$slice_array[$i]){
         array_push($result,$slice_array[$i]);
     }
}
print_r($result);
 ?>

输出

Array ( [0] => 2 [1] => 6 [2] => 10 )

PHP增长最快的子序列

2 个答案: