◤Allen Blue◢

摘要： Remove Duplicates from Sorted List IIGiven a sorted linked list, delete all nodes that have duplicate numbers, leaving onlydistinctnumbers from the original list.For example,Given1->2->3->3->4->4->5, return1->2->5.Given1->1->1->2->3, return2->3.题目意思：凡是给定链表里出现的重 阅读全文

摘要： Copy List with Random PointerA linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.Return a deep copy of the list.题目意思：深拷贝一个给定的带random指针的链表，这个random指针可能会指向其他任意一个节点或者是为null。（又是链表啊啊啊啊啊啊啊！！！！！！！！Orz……）解题思路：在每个原来节点的后面插入一个新节点（la 阅读全文

摘要： 链表相加You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.Input:(2 -> 4 -> 3) + (5 -> 6 -> 4)Output:7 -> 0 -> 8题目意思：给定两个链表，返回其相加 阅读全文

摘要： 全排列Given a collection of numbers, return all possible permutations.For example,[1,2,3]have the following permutations:[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2], and[3,2,1].题目意思：给定一个集合，求全排列。解题思路：一般的话，有两种思路可以考虑。递归和DFS遍历树。这里我只用了递归的方法，关于怎么建一棵树然后DFS，可以参考 这里。这对于练习对递归的理解真是个不错的题目。以[1,2,3]举例，可以用纸笔画一画，分别以1,2,3为 阅读全文