leetcode每日一题之5.猜字谜

猜字谜

解法

首先将word单词进行二进制压缩，重复的单词去掉，组成sword哈希映射。然后循环puzzle，先求出puzzle的所有解（这个可以用leetcode每日一题之4.子集来求），然后在sword中匹配，加上相应的数量。代码如下

class Solution {

    /**
     * @param String[] $words
     * @param String[] $puzzles
     * @return Integer[]
     */
    function findNumOfValidWords($words, $puzzles) {
        // 首先构造相关的数据结构
        $swords = [];
        foreach($words as $word){
            $length = strlen($word);
            $wordValue = 0;
            for($i = 0; $i < $length; $i++){
                $wordValue |= (1 << ord($word[$i]) - ord('a'));
            }
            if ($this->countOne($wordValue) <= 7){
                $swords[$wordValue] = isset($swords[$wordValue]) ? $swords[$wordValue] + 1 : 1;
            }
        }

        $spuzzle = [];
        foreach($puzzles as $puzzle){
            $total = 0;
            $test = (1 << ord($puzzle[0]) - ord('a'));
            if(array_key_exists($test, $swords)) $total += $swords[$test];
            // 求出谜面所有的解
            $puzzleValue = 0;
            $length = strlen($puzzle);
            $tmps = [$test];
            for($i = 1; $i < $length; $i++){
                foreach($tmps as $tmp){
                    $test = $tmp | (1 << ord($puzzle[$i]) - ord('a'));
                    if(array_key_exists($test, $swords)) $total += $swords[$test];
                    $tmps[] = $test;
                }
            }
            $spuzzle[] = $total;
        }

        return $spuzzle;

    }

    function countOne($n){
        $string = decbin($n);
        $number = 0;
        $count = strlen($string);
        for($i = 0; $i < $count; $i++){
            if($string[$i] == 1) $number++;
        }
        return $number;
    }
}