计算微博上一个题目的脚本！

script.php

<?php
$allSortFile = "allSort.txt" ;
if (!file_exists($allSortFile)){
    $fout = fopen($allSortFile,"w");
    $allSolution = allSort(1,10);
    foreach($allSolution as $item){
        $line = implode("\t",$item) ;
        fputs($fout,$line . "\n") ;
    }
    fclose($fout) ;
}
$fin = fopen($allSortFile,"r") ;
$i = 0;
while(!feof($fin)) {
    $i ++ ;
    $line = trim(fgets($fin));
    if (empty($line)) continue;
    $keys = array('_1','_2','_3','_4','_5','_6','_7','_8','_9','_10') ;
    $arrLine = explode("\t",$line);
    $arr = array_combine($keys,$arrLine);
    if (checkSolution($arr)) {
        print_r($arr) ;
    }
    if ($i % 10000 == 0){
        echo "try {$i} times ...\n" ;
    }
}

function allSort($start,$end){
	if ($start > $end){
		throw new Exception("error") ;
	}
	elseif ($start == $end){
		$rt = array();
		for ($j = 'A'; $j <= 'D'; $j ++){

			$rt[] = array("_$start"=>$j) ;
		}
		return $rt ;
	} 
	else {
		$first = $start ;
		$midRes = array();
		$solution = array();
		for ($j = 'A'; $j <= 'D'; $j ++){
			$midRes["_$first"] = $j ;
			$remain = allSort($first+1,$end);
			foreach ($remain as $one){
				$midRes = array_merge($midRes,$one);
				$solution[] = $midRes ;
			}
		}
		return $solution ;
	}
}

function checkSolution(array $arr) {
	//1
	$opt1 = array('A'=>'_1','B'=>'_2','C'=>'_3','D'=>'_4');
	$firstA = array_search('A',$arr);
	if ($firstA != $opt1[$arr['_1']]) {
		return false ;
	}
	//2
	$opt2 = array(
		'A'=>5,
		'B'=>6,
		'C'=>7,
		'D'=>8,
	);
	$find = false ;
	for($i=1;$i<=9;$i++){
		$j = $i + 1;
		if ($arr["_$i"] == $arr["_$j"]){
			$find = true ;
			break ;
		}
	}
	if (!$find || $i != $opt2[$arr["_2"]] ){
		return false ;
	} 
	//3
	$opt3 = array(
		'A'=>4,'B'=>9,'C'=>8,'D'=>2,
	);
	$k = "_" . $opt3[$arr["_3"]] ;
	if ($arr["_3"] != $arr[$k]){
		return false ;
	}
	//4
	$opt4 = array(
		'A'=>5,'B'=>4,'C'=>3,'D'=>2,
	);
	$totalA = count(array_filter($arr,function($v){
		return 'A' == $v ;
	}));
	if ($totalA != $opt4[$arr["_4"]]) {
		return false ;
	}
	//5
	$opt5 = array(
		'A'=>1,'B'=>2,'C'=>3,'D'=>4,
	);
	if ($arr["_5"] != $arr['_'.$opt5[$arr["_5"]]]) {
		return false;
	}
	//6
	$arrStat = array();
	for ($j = 'A'; $j <= 'D'; $j ++){
		$arrStat[$j] = count(array_filter($arr,function($v)use($j){
			return ($j == $v) ;
		}));
	}
	$find = false;
	if ('B' == $arr["_6"] || 'C' == $arr["_6"]) {
		if ($arrStat['C'] == $arrStat['A']) {
			$find = true ;
		}
	} elseif('D'== $arr["_6"] ) {
		if ($arrStat['A'] == $arrStat['D']){
			$find = true ;
		}
	} else {
		if ($arrStat['A'] != $arrStat['B']
			&& $arrStat['A'] != $arrStat['C']
			&& $arrStat['D'] != $arrStat['D'] ){
			$find = true ;
		} 
	}
	if (!$find) {
		return false ;
	}
	//7
	$opt7 = array(
		'A'=>3,'B'=>2,'C'=>1,'D'=>0,
	);
	if ($opt7[$arr["_7"]] != abs($arr["_7"]-$arr["_8"])) {
		return false;
	}
	//8
	$opt8 = array(
		'A'=>0,'B'=>1,'C'=>2,'D'=>3,
	);
	if ($opt8[$arr['_8']] != $arrStat['A']){
		return false;
	}
	//9
	$flag = false;
	$count = $arrStat['B'] + $arrStat['C'] + $arrStat['D'] ;
	switch($arr['_9']) {
		case 'A':
			if (in_array($count,array(4,6,8,10))){
				$flag = true;
			}
			break;
		case 'B':
			if (in_array($count,array(2,3,5,7))){
				$flag = true;
			}
			break;
		case 'C':
			if ($count < 5){
				$flag = true;
			}
			break;
		case 'D':
			if (in_array($count,array(1,4,9))){
				$flag = true;
			}
			break;
	}
	if (!$flag){
		return false;
	}
	//10
	return true;
}