Question

我的结果数组在这里会发生什么？我希望结果数组的大小等于输入数组，但缺少3个条目..它们去了哪里？他们没有像他们原本那样去追回......

代码：

<?php
init();
$list_xy = array(
    0 => array(
        'id' => '308',
        'x' => '37',
        'y' => '63'
    ),
    1 => array(
        'id' => '963',
        'x' => '38',
        'y' => '134'
    ),
    2 => array(
        'id' => '385',
        'x' => '39',
        'y' => '132'
    ),
    3 => array(
        'id' => '1231',
        'x' => '50',
        'y' => '199'
    ),
    4 => array(
        'id' => '788',
        'x' => '51',
        'y' => '59'
    ),
    5 => array(
        'id' => '1151',
        'x' => '53',
        'y' => '61'
    ),
    6 => array(
        'id' => '671',
        'x' => '55',
        'y' => '60'
    ),
    7 => array(
        'id' => '1487',
        'x' => '55',
        'y' => '55'
    )
);
$sorted_list_xy = sort_by_xy_distance($list_xy);
$sorted_list_xy_size = count($sorted_list_xy, COUNT_NORMAL);
$list_xy_size = count($list_xy, COUNT_NORMAL);
var_dump($sorted_list_xy_size == $list_xy_size ? "looks right" : "something is wrong", $sorted_list_xy_size, $list_xy_size);
die("died");


function sort_by_xy_distance($input_list)
{
    $ret = array();
    $a = $input_list[0];
    array_push($ret, $input_list[0]);
    $input_list[0] = null;
    $i = 1;
    for ($i = 1; $i < count($input_list); ++$i) {
        if ($input_list[$i] == null) {
            echo 'already added to list..';
            continue;
        }
        $ii = 1;
        $tmpdistance = 0;
        $nearest = array(
            'index' => -1,
            'distance' => PHP_INT_MAX
        );
        for ($ii = 1; $ii < count($input_list); ++$ii) {
            if ($input_list[$ii] == null || $ii == $i) {
                //echo 'already added to list..';
                continue;
            }
            $tmpdistance = abs($input_list[$ii]['x'] - $a['x']) + abs($input_list[$ii]['y'] - $a['y']);
            if ($tmpdistance < $nearest['distance']) {
                $nearest['index'] = $ii;
                $nearest['distance'] = $tmpdistance;
            }
        }
        assert($nearest['index'] != -1);
        array_push($ret, $input_list[$nearest['index']]);
        $a = $input_list[$nearest['index']];
        $input_list[$nearest['index']] = null;
    }
    return $ret;
}





function init()
{
    error_reporting(E_ALL);
    set_error_handler("exception_error_handler");
}
function exception_error_handler($errno, $errstr, $errfile, $errline)
{
    if (!(error_reporting() & $errno)) {
        // This error code is not included in error_reporting
        return;
    }
    throw new ErrorException($errstr, 0, $errno, $errfile, $errline);
}

输出：

已添加到list ..已添加到list..already已添加到 list..string（18）“出错了”int（5）int（8）去世了

预期输出:(类似于）

已添加到list ..已添加到list..already已添加到 list..string（11）“看起来正确”int（8）int（8）去世

我期望列表转到：一个列表，其中与下一个[x] [y]的差异尽可能小，这将是：

array(8) {
  [0]=>
  array(3) {
    ["id"]=>
    string(3) "308"
    ["x"]=>
    string(2) "37"
    ["y"]=>
    string(2) "63"
  }
  [1]=>
  array(3) {
    ["id"]=>
    string(3) "788"
    ["x"]=>
    string(2) "51"
    ["y"]=>
    string(2) "59"
  }
  [2]=>
  array(3) {
    ["id"]=>
    string(4) "1151"
    ["x"]=>
    string(2) "53"
    ["y"]=>
    string(2) "61"
  }
  [3]=>
  array(3) {
    ["id"]=>
    string(3) "671"
    ["x"]=>
    string(2) "55"
    ["y"]=>
    string(2) "60"
  }
  [4]=>
  array(3) {
    ["id"]=>
    string(4) "1487"
    ["x"]=>
    string(2) "55"
    ["y"]=>
    string(2) "55"
  }
  [5]=>
  array(3) {
    ["id"]=>
    string(3) "385"
    ["x"]=>
    string(2) "39"
    ["y"]=>
    string(3) "132"
  }
  [6]=>
  array(3) {
    ["id"]=>
    string(3) "963"
    ["x"]=>
    string(2) "38"
    ["y"]=>
    string(3) "134"
  }
  [7]=>
  array(3) {
    ["id"]=>
    string(4) "1231"
    ["x"]=>
    string(2) "50"
    ["y"]=>
    string(3) "199"
  }
}

我很擅长制作图形插图，但生病了。这是我的地图： map http://imagizer.imageshack.us/a/img633/3521/E0HGRe.png

我需要访问所有的黑点。这是我目前的路径： enter image description here

这条路径不是很优秀.. 这是我想要的路径： enter image description here

这就是排序功能试图找到的，这是访问所有黑点的最短路径。

Answer 1

距离计算你应该使用毕达哥拉斯＆＃39;定理（或只是hypot，如@prodigitalson提到的那样）。对于地理坐标，您可以使用：http://www.movable-type.co.uk/scripts/latlong.html

让我们修复您的代码。第一个循环的每一步都应该从输入值中取一个值并将其放入结果中。但它继续在里面，因此第一循环的一些步骤不能完成它们的工作。尝试删除第一个继续。

$list_xy = array(
    0 => array(
        'id' => '308',
        'x' => '37',
        'y' => '63'
    ),
    1 => array(
        'id' => '963',
        'x' => '38',
        'y' => '134'
    ),
    2 => array(
        'id' => '385',
        'x' => '39',
        'y' => '132'
    ),
    3 => array(
        'id' => '1231',
        'x' => '50',
        'y' => '199'
    ),
    4 => array(
        'id' => '788',
        'x' => '51',
        'y' => '59'
    ),
    5 => array(
        'id' => '1151',
        'x' => '53',
        'y' => '61'
    ),
    6 => array(
        'id' => '671',
        'x' => '55',
        'y' => '60'
    ),
    7 => array(
        'id' => '1487',
        'x' => '55',
        'y' => '55'
    )
);
$sorted_list_xy = sort_by_xy_distance($list_xy);
$sorted_list_xy_size = count($sorted_list_xy, COUNT_NORMAL);
$list_xy_size = count($list_xy, COUNT_NORMAL);
var_dump($sorted_list_xy_size == $list_xy_size ? "looks right" : "something is wrong", $sorted_list_xy_size, $list_xy_size);
die("died");

function sort_by_xy_distance($input_list)
{
    $ret = array();
    $a = $input_list[0];
    array_push($ret, $input_list[0]);
    $input_list[0] = null;
    $i = 1;
    for ($i = 1; $i < count($input_list); ++$i) {
//                                                         up here
//        if ($input_list[$i] == null) {
//            echo 'already added to list..';
//            continue;
//        }
        $ii = 1;
        $tmpdistance = 0;
        $nearest = array(
            'index' => -1,
            'distance' => PHP_INT_MAX
        );
        for ($ii = 1; $ii < count($input_list); ++$ii) {
            if ($input_list[$ii] == null || $ii == $i) {
                //echo 'already added to list..';
                continue;
            }
            $tmpdistance = abs($input_list[$ii]['x'] - $a['x']) + abs($input_list[$ii]['y'] - $a['y']);
            if ($tmpdistance < $nearest['distance']) {
                $nearest['index'] = $ii;
                $nearest['distance'] = $tmpdistance;
            }
        }
        assert($nearest['index'] != -1);
        array_push($ret, $input_list[$nearest['index']]);
        $a = $input_list[$nearest['index']];
        $input_list[$nearest['index']] = null;
    }
    return $ret;
}

我的阵列会发生什么？物品消失了

1 个答案: