題目描述
輸入兩個單調遞增的鏈表,輸出兩個鏈表合成後的鏈表,當然我們需要合成後的鏈表滿足單調不減規則。
function Merge($pHead1, $pHead2)
{
if($pHead1 == NULL) return $pHead2;
if($pHead2 == NULL) return $pHead1;
$re = new ListNode();
if ($pHead1 -> val <= $pHead2 -> val) {
$re = $pHead1;
$pHead1 = $pHead1 -> next;
} else {
$re = $pHead2;
$pHead2 = $pHead2 -> next;
}
$p = $re;
while ($pHead2 && $pHead1) {
if ($pHead1 -> val <= $pHead2 -> val) {
$p -> next = $pHead1;
$p = $p -> next;
$pHead1 = $pHead1 -> next;
} else {
$p -> next = $pHead2;
$p = $p -> next;
$pHead2 = $pHead2 -> next;
}
}
if ($pHead2 != NULL) {
$p -> next = $pHead2;
}
if ($pHead1 != NULL) {
$p -> next = $pHead1;
}
return $re;
}