摘要： Given a binary tree, find its minimum depth.The minimum depth is the number of nodes along the shortest path from the root node down to the nearest le... 阅读全文

摘要： 很锻炼DP/recursive思路的一道题，个人感觉DP/recursive算是比较难写的题目了。这道题解法的巧妙之处在于巧用-1，并且使用临时存储，节省了很多开支。这道题同时也在Career Cup上面出现过 这道题我两次调试通过，第一次错是因为input{}, output false, exp 阅读全文

摘要： Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest le... 阅读全文

摘要： Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical and the nodes have the same value. 1 public... 阅读全文

摘要： Given a sorted linked list, delete all duplicates such that each element appear only once.For example,Given 1->1->2, return 1->2.Given 1->1->2->3->3, ... 阅读全文

摘要： Given a non-negative number represented as an array of digits, plus one to the number.The digits are stored such that the most significant digit is at... 阅读全文

摘要： Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.If the last word ... 阅读全文

摘要： Given an array and a value, remove all instances of that value in place and return the new length.The order of elements can be changed. It doesn't mat... 阅读全文

摘要： 没有想通为什么这个简单的问题竟然不是那么简单，太小看它了，以下是别人的很不错的solution: Solution: 做法是维护两个指针，一个保留当前有效元素的长度，一个从前往后扫，然后跳过那些重复的元素。因为数组是有序的，所以重复元素一定相邻，不需要额外记录。时间复杂度是O(n)，空间复杂度O(1 阅读全文