


Example analysis of deep chronological maze generation of PHP trees and A* automatic pathfinding algorithm, maze example analysis
This article describes the deep chronological generation of mazes and A* of PHP trees through examples *Automatic pathfinding algorithm. Share it with everyone for your reference. The specific analysis is as follows:
A colleague recommended Sansi’s maze algorithm. After reading it, I thought it was pretty good, so I converted it to PHP
Sansi's maze algorithm uses the principle of tree depth traversal. The maze generated in this way is quite thin, and the number of dead ends is relatively small!
There is only one path between any two points.
As for the A* pathfinding algorithm, it is the most popular fully automatic pathfinding algorithm
No further nonsense, just paste the code
Maze generation class:
Copy code The code is as follows: class Maze{
// Maze Create
private $_w;
private $_h;
Private $_grids;
private $_walkHistory;
Private $_walkHistory2;
Private $_targetSteps;
// Construct
Public function Maze() {
$this->_w = 6;
$this->_h = 6;
$this->_grids = array();
}
//Set the maze size
Public function set($width = 6, $height = 6) {
If ( $width > 0 ) $this->_w = $width;
If ( $height > 0 ) $this->_h = $height;
return $this;
}
// Get the maze
Public function get() {
return $this->_grids;
}
// Generate maze
Public function create() {
$this->_init();
return $this->_walk(rand(0, count($this->_grids) -1 ));
}
// Get the dead end point
Public function block($n = 0, $rand = false) {
$l = count($this->_grids);
for( $i = 1; $i
$v = $this->_grids[$i];
If ( $v == 1 || $v == 2 || $v == 4 || $v == 8 ) {
$return[] = $i;
}
}
// Randomly pick points
if ( $rand ) shuffle($return);
if ( $n == 0 ) return $return;
if ( $n == 1 ) {
return array_pop($return);
} else {
return array_slice($return, 0, $n);
}
}
/**
|------------------------------------------------- ---------------
| | Series of functions to generate maze
|------------------------------------------------- ---------------
*/
Private function _walk($startPos) {
$this->_walkHistory = array();
$this->_walkHistory2 = array();
$curPos = $startPos;
while ($this->_getNext0() != -1) {
$curPos = $this->_step($curPos);
if ( $curPos === false ) break;
}
return $this;
}
Private function _getTargetSteps($curPos) {
$p = 0;
$a = array();
$p = $curPos - $this->_w;
If ($p > 0 && $this->_grids[$p] === 0 && ! $this->_isRepeating($p)) {
array_push($a, $p);
} else {
array_push($a, -1);
}
$p = $curPos + 1;
if ($p % $this->_w != 0 && $this->_grids[$p] === 0 && ! $this->_isRepeating($p)) {
array_push($a, $p);
} else {
array_push($a, -1);
}
$p = $curPos + $this->_w;
if ($p _grids) && $this->_grids[$p] === 0 && ! $this->_isRepeating($p)) {
array_push($a, $p);
} else {
array_push($a, -1);
}
$p = $curPos - 1;
if (($curPos % $this->_w) != 0 && $this->_grids[$p] === 0 && ! $this->_isRepeating($p)) {
array_push($a, $p);
} else {
array_push($a, -1);
}
return $a;
}
private function _noStep() {
$l = count($this->_targetSteps);
for ($i = 0; $i
if ($this->_targetSteps[$i] != -1) return false;
}
return true;
}
private function _step($curPos) {
$this->_targetSteps = $this->_getTargetSteps($curPos);
if ( $this->_noStep() ) {
if ( count($this->_walkHistory) > 0 ) {
$tmp = array_pop($this->_walkHistory);
} else {
return false;
}
array_push($this->_walkHistory2, $tmp);
return $this->_step($tmp);
}
$r = rand(0, 3);
while ( $this->_targetSteps[$r] == -1) {
$r = rand(0, 3);
}
$nextPos = $this->_targetSteps[$r];
$isCross = false;
if ( $this->_grids[$nextPos] != 0)
$isCross = true;
if ($r == 0) {
$this->_grids[$curPos] ^= 1;
$this->_grids[$nextPos] ^= 4;
} elseif ($r == 1) {
$this->_grids[$curPos] ^= 2;
$this->_grids[$nextPos] ^= 8;
} elseif ($r == 2) {
$this->_grids[$curPos] ^= 4;
$this->_grids[$nextPos] ^= 1;
} elseif ($r == 3) {
$this->_grids[$curPos] ^= 8;
$this->_grids[$nextPos] ^= 2;
}
array_push($this->_walkHistory, $curPos);
return $isCross ? false : $nextPos;
}
private function _isRepeating($p) {
$l = count($this->_walkHistory);
for ($i = 0; $i
if ($this->_walkHistory[$i] == $p) return true;
}
$l = count($this->_walkHistory2);
for ($i = 0; $i
if ($this->_walkHistory2[$i] == $p) return true;
}
return false;
}
private function _getNext0() {
$l = count($this->_grids);
for ($i = 0; $i
if ( $this->_grids[$i] == 0) return $i;
}
return -1;
}
private function _init() {
$this->_grids = array();
for ($y = 0; $y _h; $y ++) {
for ($x = 0; $x _w; $x ++) {
array_push($this->_grids, 0);
}
}
return $this;
}
}
A*寻路算法
复制代码 代码如下:class AStar{
// A-star
private $_open;
private $_closed;
private $_start;
private $_end;
private $_grids;
private $_w;
private $_h;
// Construct
public function AStar(){
$this->_w = null;
$this->_h = null;
$this->_grids = null;
}
public function set($width, $height, $grids) {
$this->_w = $width;
$this->_h = $height;
$this->_grids = $grids;
return $this;
}
// 迷宫中寻路
public function search($start = false, $end = false) {
return $this->_search($start, $end);
}
/**
|------------------------------------------------- ---------------
| Automatic path finding - A-star algorithm
|------------------------------------------------- ---------------
*/
public function _search($start = false, $end = false) {
if ( $start !== false ) $this->_start = $start;
if ( $end !== false ) $this->_end = $end;
$_sh = $this->_getH($start);
$point['i'] = $start;
$point['f'] = $_sh;
$point['g'] = 0;
$point['h'] = $_sh;
$point['p'] = null;
$this->_open[] = $point;
$this->_closed[$start] = $point;
while ( 0 _open) ) {
$minf = false;
foreach( $this->_open as $key => $maxNode ) {
if ( $minf === false || $minf > $maxNode['f'] ) {
$minIndex = $key;
}
}
$nowNode = $this->_open[$minIndex];
unset($this->_open[$minIndex]);
if ( $nowNode['i'] == $this->_end ) {
$tp = array();
while( $nowNode['p'] !== null ) {
array_unshift($tp, $nowNode['p']);
$nowNode = $this->_closed[$nowNode['p']];
}
array_push($tp, $this->_end);
break;
}
$this->_setPoint($nowNode['i']);
}
$this->_closed = array();
$this->_open = array();
return $tp;
}
private function _setPoint($me) {
$point = $this->_grids[$me];
// 所有可选方向入队列
if ( $point & 1 ) {
$next = $me - $this->_w;
$this->_checkPoint($me, $next);
}
if ( $point & 2 ) {
$next = $me + 1;
$this->_checkPoint($me, $next);
}
if ( $point & 4 ) {
$next = $me + $this->_w;
$this->_checkPoint($me, $next);
}
if ( $point & 8 ) {
$next = $me - 1;
$this->_checkPoint($me, $next);
}
}
private function _checkPoint($pNode, $next) {
if ( $this->_closed[$next] ) {
$_g = $this->_closed[$pNode]['g'] + $this->_getG($next);
if ( $_g
$this->_closed[$next]['g'] = $_g;
$this->_closed[$next]['f'] = $this->_closed[$next]['g'] + $this->_closed[$next]['h'];
$this->_closed[$next]['p'] = $pNode;
}
} else {
$point['p'] = $pNode;
$point['h'] = $this->_getH($next);
$point['g'] = $this->_getG($next);
$point['f'] = $point['h'] + $point['g'];
$point['i'] = $next;
$this->_open[] = $point;
$this->_closed[$next] = $point;
}
}
private function _getG($point) {
return abs($this->_start - $point);
}
private function _getH($point) {
return abs($this->_end - $point);
}
}
完整实例代码点击此处本站下载。
有需要大家可以直接下demo,看看效果!
希望本文所述对大家的php程序设计有所帮助。

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实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

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在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。


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