1.使用遞歸和非遞歸實現鏈表的合併
輸入兩個單調遞增的鏈表,輸出兩個鏈表合成後的鏈表,要求合成後的鏈表滿足單調不減規則。
2.代碼實現
struct ListNode {
int val;
struct ListNode *next;
ListNode(int x) : val(x), next(NULL) {}
};
/*遞歸實現合併兩個排序鏈表*/
ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
{
if(pHead1 == NULL)
return pHead2;
if(pHead2 == NULL)
return pHead1;
if(pHead1->val < pHead2->val)
{
pHead1->next = Merge(pHead1->next, pHead2);
return pHead1;
}
else
{
pHead2->next = Merge(pHead1, pHead2->next);
return pHead2;
}
}
/*非遞歸實現合併兩個排序鏈表*/
ListNode* Merge(ListNode* pHead1, ListNode* pHead2)
{
ListNode *pHead = new ListNode(0);
ListNode *p = pHead;
while(pHead1 != NULL && pHead2 != NULL)
{
if(pHead1->val < pHead2->val)
{
p->next = pHead1;
pHead1 = pHead1->next;
}
else
{
p->next = pHead2;
pHead2 = pHead2->next;
}
p = p->next;
}
if(pHead1 != NULL)
{
p->next = pHead1;
}
if(pHead2 != NULL)
{
p->next = pHead2;
}
return pHead->next;
}