"; // 找到了 if($arrData[$i] == $val) return $i; } return -1; } // 测试顺序查找 $arrData = array(4,51,6,73,2,5,9,33,50,3,4,6,1,4,67); echo normal_search($arrData,6),"
"; echo normal_search($arrData,66),"
"; // 二分法查找(针对有序的列进行查找) function binary_search($arrData,$val) { $len = count($arrData); if($len == 0) return -1; $start = 0; $end = $len - 1; while($start <= $end) { $middle = intval(($start + $end)/2); echo "start = ",$start," end = ",$end," middle = ",$middle,"
"; if($arrData[$middle] == $val) { return $middle; } elseif ($arrData[$middle] > $val) { $end = $middle - 1 ; } elseif ($arrData[$middle] < $val) { $start = $middle + 1; } } return -1; } // 测试一下二分法查找 $arrData = array(1,2,3,4,5,7,8,9,11,23,56,100,104,578,1000); echo binary_search($arrData,578),"
"; echo binary_search($arrData,66),"
";