LeetCode 147. Insertion Sort List 链表插入排序 C++/Java
Sort a linked list using insertion sort.
A graphical example of insertion sort. The partial sorted list (black) initially contains only the first element in the list.
With each iteration one element (red) is removed from the input data and inserted in-place into the sorted list
Algorithm of Insertion Sort:
1 Insertion sort iterates, consuming one input element each repetition, and growing a sorted output list. 2 At each iteration, insertion sort removes one element from the input data, finds the location it belongs within the sorted list, and inserts it there. 3 It repeats until no input elements remain.Example 1:
Input: 4->2->1->3 Output: 1->2->3->4Example 2:
Input: -1->5->3->4->0 Output: -1->0->3->4->5解題思路:將原鏈表中元素一個一個取出來,在新鏈表中比較進(jìn)行排序。時間復(fù)雜度為O(n2),是一種效率并不是很高的算法,但是空間復(fù)雜度為O(1),以高時間復(fù)雜度換取了低空間復(fù)雜度。
方法一(C++)
?
1 ListNode* insertionSortList(ListNode* head) { 2 ListNode* dummy=new ListNode(-1),*cur=dummy; 3 while(head){ 4 ListNode* t=head->next; 5 cur=dummy; 6 while(cur->next&&cur->next->val<=head->val) 7 cur=cur->next; 8 head->next=cur->next; 9 cur->next=head; 10 head=t; 11 } 12 return dummy->next; 13 }?
(Java)
1 public ListNode insertionSortList(ListNode head) { 2 ListNode dummy=new ListNode(-1),cur=dummy; 3 while(head!=null){ 4 ListNode t=head.next; 5 cur=dummy; 6 while(cur.next!=null&&cur.next.val<=head.val) 7 cur=cur.next; 8 head.next=cur.next; 9 cur.next=head; 10 head=t; 11 } 12 return dummy.next; 13 }方法二:不符合題目中的要求,只是完成最基本的鏈表排序功能,借助vector中的sort排序方法。(C++)
1 ListNode* insertionSortList(ListNode* head) { 2 vector<int> m; 3 while(head){ 4 m.push_back(head->val); 5 head=head->next; 6 } 7 sort(m.begin(),m.end()); 8 ListNode* newhead=new ListNode(-1); 9 while(!m.empty()){ 10 ListNode* cur=new ListNode(m.back()); 11 m.pop_back(); 12 cur->next=newhead->next; 13 newhead->next=cur; 14 } 15 return newhead->next; 16 }?
posted on 2019-03-29 10:58?木落長安rr 閱讀(...) 評論(...) 編輯 收藏轉(zhuǎn)載于:https://www.cnblogs.com/hhhhan1025/p/10619875.html
總結(jié)
以上是生活随笔為你收集整理的LeetCode 147. Insertion Sort List 链表插入排序 C++/Java的全部內(nèi)容,希望文章能夠幫你解決所遇到的問題。
- 上一篇: Python 输出的空格问题
- 下一篇: QT-- MainWindow外的cpp