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Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x.
You should preserve the original relative order of the nodes in each of the two partitions.
For example,
Given 1->4->3->2->5->2 and x = 3,
return 1->2->2->4->3->5.
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode* partition(ListNode* head, int x) { ListNode* pivot = NULL; ListNode* cur = head; ListNode* insert_pos = cur; ListNode* insert_pos_pre = NULL; while(cur && cur->val < x){ insert_pos_pre = cur; cur = cur->next; insert_pos = cur; } pivot = cur; /* pivot 左边做插入，insert_node_pre,inser_node pivot 右边做删除, delete_node_pre,delete_node */ ListNode* possible_delete_node_pre = pivot; ListNode* possible_delete_node = pivot ? pivot->next : NULL; while(possible_delete_node){ ListNode* possible_delete_node_next = possible_delete_node->next; if(possible_delete_node->val < x){ if(insert_pos_pre){ insert_pos_pre->next = possible_delete_node ; }else{ head = possible_delete_node; } possible_delete_node->next = insert_pos; insert_pos_pre = possible_delete_node; insert_pos = insert_pos_pre->next; possible_delete_node_pre ->next = possible_delete_node_next; }else{ possible_delete_node_pre = possible_delete_node; } possible_delete_node = possible_delete_node_next; } return head; } };
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原文地址：http://www.cnblogs.com/zengzy/p/5041976.html
