将给定的链表向右转动k个位置,k是非负数。
例如:
给定1->2->3->4->5->null , k=2,
返回4->5->1->2->3->null。
<?php
class Node {
public $next = null;
public $val;
public function __construct($val) {
$this->val = $val;
}
}
function rotateRight($head, $k) {
$len = 0;
$node = $head;
while ($head != null) {
$len ++;
$pre = $head;
$head = $head->next;
}
$pre->next = $node;
for ($i = 0; $i < $len - $k; $i ++) {
$pre = $pre->next;
}
$retNode = $pre->next;
$pre->next = null;
return $retNode;
}
$node1 = new Node(1);
$node2 = new Node(2);
$node3 = new Node(3);
$node4 = new Node(4);
$node1->next = $node2;
$node2->next = $node3;
$node3->next = $node4;
$ret = rotateRight($node1, 2);
while ($ret != null) {
print $ret->val;
$ret = $ret->next;
}