编写代码,以给定值x为基准将链表分割成两部分,所有小于x的结点排在大于或等于x的结点之前
给定一个链表的头指针 ListNode* pHead,请返回重新排列后的链表的头指针。注意:分割以后保持原来的数据顺序不变。
思路:
/*
struct ListNode {
int val;
struct ListNode *next;
ListNode(int x) : val(x), next(NULL) {}
};*/
class Partition {
public:
ListNode* partition(ListNode* Head, int x) {
// write code here
if(Head == nullptr){
return nullptr;
}//if
ListNode *smallList = new ListNode(-1);
ListNode *bigList = new ListNode(-1);
ListNode *ps = smallList,*pb = bigList,*cur = Head;
while(cur){
if(cur->val < x){
ps->next = cur;
ps = cur;
}//if
else{
pb->next = cur;
pb = cur;
}//else
cur = cur->next;
}//while
pb->next = nullptr;
ps->next = bigList->next;
return smallList->next;
}
};
/*
struct ListNode {
int val;
struct ListNode *next;
ListNode(int x) : val(x), next(NULL) {}
};*/
class Partition {
public:
ListNode* partition(ListNode* pHead, int x) {
// write code here
ListNode *small=new ListNode(0);
ListNode *large=new ListNode(0);
ListNode* smallhead=small;
ListNode* largehead=large;
while(pHead){
if(pHead->val<x){
small->next=pHead;
small=small->next;
} else {
large->next=pHead;
large=large->next;
}
pHead=pHead->next;
}
large->next=NULL;
small->next=largehead->next;
return smallhead->next;
}
};