php操作字符串及数组实现相似度算法

function closest_word($input, $words) {
    $shortest = -1;
    foreach ($words as $word) {
     $lev = levenshtein($input, $word);
     if ($lev == 0) {
      $closest = $word;
      $shortest = 0;
      break;
     }
     if ($lev <= $shortest || $shortest < 0) {
      $closest = $word;
      $shortest = $lev;
     }
    }
    return $closest;
}

// 根据传入的州名（可能客户有输错），返回相似度最高的州名称
$united_state_list = array(
'AL'=>"Alabama",
'AK'=>"Alaska",
'AZ'=>"Arizona",
'AR'=>"Arkansas",
'CA'=>"California",
'CO'=>"Colorado",
'CT'=>"Connecticut",
'DE'=>"Delaware",
'DC'=>"District Of Columbia",
'FL'=>"Florida",
'GA'=>"Georgia",
'HI'=>"Hawaii",
'ID'=>"Idaho",
'IL'=>"Illinois",
'IN'=>"Indiana",
'IA'=>"Iowa",
'KS'=>"Kansas",
'KY'=>"Kentucky",
'LA'=>"Louisiana",
'ME'=>"Maine",
'MD'=>"Maryland",
'MA'=>"Massachusetts",
'MI'=>"Michigan",
'MN'=>"Minnesota",
'MS'=>"Mississippi",
'MO'=>"Missouri",
'MT'=>"Montana",
'NE'=>"Nebraska",
'NV'=>"Nevada",
'NH'=>"New Hampshire",
'NJ'=>"New Jersey",
'NM'=>"New Mexico",
'NY'=>"New York",
'NC'=>"North Carolina",
'ND'=>"North Dakota",
'OH'=>"Ohio",
'OK'=>"Oklahoma",
'OR'=>"Oregon",
'PA'=>"Pennsylvania",
'RI'=>"Rhode Island",
'SC'=>"South Carolina",
'SD'=>"South Dakota",
'TN'=>"Tennessee",
'TX'=>"Texas",
'UT'=>"Utah",
'VT'=>"Vermont",
'VA'=>"Virginia",
'WA'=>"Washington",
'WV'=>"West Virginia",
'WI'=>"Wisconsin",
'WY'=>"Wyoming"
);
$input_state = 'Wiscsin';
$state = closest_word($input_state ,array_values($united_state_list));
echo $state;