Leetcode 147. Insertion Sort List(链表实现快排)

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147. Insertion Sort List

Total Accepted: 66609 Total Submissions: 230331 Difficulty: Medium

Sort a linked list using insertion sort.

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链接: https://leetcode.com/problems/insertion-sort-list/

#include<iostream>#include<algorithm>#include<cstdio>#include<cstring>#include<stack>#include<queue>#include<cmath>#include<map>#include<set>typedef long long ll;#define eps 1e-8#define L(x) (x<<1)#define R(x) (x<<1|1)#define MID(x,y) ((x+y)>>1)#define bug printf("hi"\n)using namespace std;#define INF 0x3f3f3f3f#define N 30struct ListNode{int val;ListNode *next;ListNode(int x):val(x),next(NULL){}};void show(ListNode * head){while(head){printf("%d ",head->val);head=head->next;}printf("\n");}class Solution{public:ListNode *insertionSortList(ListNode * head){if(head==NULL||head->next==NULL) return head;ListNode* pre=new ListNode(0);quicksort(pre,head,NULL);head=pre->next;delete pre;return head;}ListNode * quicksort(ListNode* pre,ListNode * head,ListNode *tail){if(head==tail) return head;if(head->next==NULL) return head;ListNode * mid=getpos(pre,head,tail);quicksort(pre,pre->next,mid);quicksort(mid,mid->next,tail);return pre;}ListNode * getpos(ListNode* pre,ListNode *head,ListNode * tail){ListNode *small=new ListNode(0),*big=new ListNode(0);ListNode *ss=small,*bb=big;for(ListNode * it=head->next;it!=tail;it=it->next)if(it->val<=head->val){small->next=it;small=it;}   else   {   big->next=it;   big=it;   }big->next=tail;head->next=bb->next;small->next=head;pre->next=ss->next;delete bb;delete ss;return head;}};int main(){int i,j;ListNode * head=new ListNode(3);ListNode * tail=head;for(int i=2;i>=1;i--){ListNode * temp=new ListNode(i);tail->next=temp;tail=temp;}show(head);Solution ans;tail=ans.insertionSortList(head);show(tail);return 0;}

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