算法编程题

　　　　1

　　3            5

    7        9      11     

 13    15      17     19

第N行相加的和是多少？

 N*N*N;

$string = "The sunset sets at twelve o\' clock.";
$arr = [
'a' => 1,
'b' => 2,
'c' => 3,
'd' => 4,
'e' => 5,
'f' => 6,
'g' => 7,
'h' => 8,
'i' => 9,
'j' => 10,
'k' => 11,
'l' => 12,
'm' => 13,
'n' => 14,
'o' => 15,
'p' => 16,
'q' => 17,
'r' => 18,
's' => 19,
't' => 20,
'u' => 21,
'v' => 22,
'w' => 23,
'x' => 24,
'y' => 25,
'z' => 26,
];
$array = str_split(preg_replace('/\'|\\\|\s|\\./gi','',strtolower($string)));
$tmp = "";
foreach($array as $v)
{
if(!empty($v) && in_array($arr[$v],$arr)){
$tmp .= $arr[$v].' ';
}
}
dump(rtrim($tmp));

替换成数字

1.设有一组关键字序列{5，8，14，20，31，55，78，81，93，97，111}，使用二分（折半）法查找关键字93需要进行多少次比较（）

A. 2

B. 3

C. 4

D. 5