Frequently Used Algo

1. 链表

链表逆转

 class Solution {
 public:
     ListNode* reverseList(ListNode* head) {
         ListNode* prev = NULL;
         while (head != NULL) {
             ListNode* next = head->next;
             head->next = prev;
             prev = head;
             head = next;
         }
         return prev;
     }
 };

findMiddle

树的{前、中、后、层}序遍历

堆排序

快排

字符串的反转