- <?php
- class TwentyFourCal {
- public $needle = 24;
- public $precision = '1e-6';
- function TwentyFourCal() {
- }
- private function notice($mesg) {
- var_dump($mesg);
- }
- /**
- * 取得用户输入方法
- */
- public function calculate($operants = array()) {
- try {
- $this->search($operants, 4);
- } catch (Exception $e) {
- $this->notice($e->getMessage());
- return;
- }
- $this->notice('can\'t compute!');
- return;
- }
- /**
- * 求24点算法PHP实现
- */
- private function search($expressions, $level) {
- if ($level == 1) {
- $result = 'return ' . $expressions[0] . ';';
- if ( abs(eval($result) - $this->needle) <= $this->precision) {
- throw new Exception($expressions[0]);
- }
- }
- for ($i=0;$i<$level;$i++) {
- for ($j=$i+1;$j<$level;$j++) {
- $expLeft = $expressions[$i];
- $expRight = $expressions[$j];
- $expressions[$j] = $expressions[$level - 1];
- $expressions[$i] = '(' . $expLeft . ' + ' . $expRight . ')';
- $this->search($expressions, $level - 1);
- $expressions[$i] = '(' . $expLeft . ' * ' . $expRight . ')';
- $this->search($expressions, $level - 1);
- $expressions[$i] = '(' . $expLeft . ' - ' . $expRight . ')';
- $this->search($expressions, $level - 1);
- $expressions[$i] = '(' . $expRight . ' - ' . $expLeft . ')';
- $this->search($expressions, $level - 1);
- if ($expLeft != 0) {
- $expressions[$i] = '(' . $expRight . ' / ' . $expLeft . ')';
- $this->search($expressions, $level - 1);
- }
- if ($expRight != 0) {
- $expressions[$i] = '(' . $expLeft . ' / ' . $expRight . ')';
- $this->search($expressions, $level - 1);
- }
- $expressions[$i] = $expLeft;
- $expressions[$j] = $expRight;
- }
- }
- return false;
- }
- function __destruct() {
- }
- }
- /* demo */
- $tf = new TwentyFourCal();
- $tf->calculate( array(4,8,8,8) );
- ?>
来源: http://www.phpxs.com/code/1003511/