Given a sorted linked list, delete all duplicates such that each element appear only once.
For example,
Given 1->1->2, return 1->2.
Given 1->1->2->3->3, return 1->2->3.
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *deleteDuplicates(ListNode *head) {
ListNode myhead(99), *prev, *s, *e;
int cnt;
prev = &myhead;
myhead.next = head;
s = head;
while (s != NULL) {
e = s->next;
cnt = 0;
while (e != NULL && e->val == s->val) e = e->next, cnt++;
if (cnt == 0) {
prev = s;
s = e;
}
else {
prev = s;
del(s->next, e);
s->next = e;
s = e;
}
}
return myhead.next;
}
void del(ListNode* s, ListNode* e) {
// delete [s, e);
ListNode *t;
while (s != e) {
t = s;
s = s->next;
delete t;
}
}
};
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *deleteDuplicates(ListNode *head) {
ListNode myhead(99);
myhead.next = head;
ListNode *prev = &myhead, *cur = head, *next;
int cnt;
while (cur != NULL) {
next = cur->next;
cnt = 0;
while (next != NULL && next->val == cur->val) next=next->next, cnt++;
if (cnt == 0) {
prev = cur;
cur = next;
}
else {
prev->next = next;
del(cur, next);
cur = next;
}
}
return myhead.next;
}
void del(ListNode* s, ListNode* e) {
// delete [s, e);
ListNode *t;
while (s != e) {
t = s;
s = s->next;
delete t;
}
}
};
Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.
For example,
Given 1->2->3->3->4->4->5, return 1->2->5.
Given 1->1->1->2->3, return 2->3.