BigSea

LeetCode——Two SumGiven an array of integers, return indices of the two numbers such that they add up to a specific target.

LeetCode——Palindrome Linked List # 234 Given a singly linked list, determine if it is a palindrome. Follow up: Could you do it in O(n) time and O(1) space?这一题的目的是判断一个单链表是否是回文链表，并且最好是在O(

LeetCode——Reverse Linked List # 206 Reverse a singly linked list.这一题的目的是反转一个单链表。是对链表操作的一个经典题目。第一个想到的思路是利用一个栈。C++语言中用栈实现的话，我只能将val保存到栈中，因为指针的问题，我解决的不好，但是Java的话，因为不用指针，就可以轻松地写出来。所以下面两个版本，其实不太一样。P

LeetCode——Merge Two Binary Trees # 617 Given two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are not.

LeetCode——Balanced Binary Tree #110 Given a binary tree, determine if it is height-balanced. For this problem, a height-balanced binary tree is defined as a binary tree in which the depth o

LeetCode——Maxium Depth of Binary Tree # 104 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 farthes

LeetCode——Linked List Cycle #141 Given a linked list, determine if it has a cycle in it. Follow up: Can you solve it without using extra space? 这一题的目的是判断链表中是否有环。一个思路是利用哈希表。如果遍历过的结点已经存在了

LeetCode——Best Time to Buy and Sell Stock # 121 Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitted to complete at most one t

LeetCode——Subtree of Another Given two non-empty binary trees s and t, check whether tree t has exactly the same structure and node values with a subtree of s. A subtree of s is a tree consists of a

LeetCode——Maximum Subarray # 53 Find the contiguous subarray within an array (containing at least one number) which has the largest sum. For example, given the array [-2,1,-3,4,-1,2,1,-5,4],

LeetCode——Climbing Stairs # 70 You are climbing a stair case. It takes n steps to reach to the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to t

LeetCode——Merge Two Sorted Lists #21 Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.

LeetCode——Single Number # 136 Given an array of integers, every element appears twice except for one. Find that single one. Note: Your algorithm should have a linear runtime complexity. Co

Leetcode——Valid Parenthese #20 Given a string containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[’ and ‘]’, determine if the input string is valid.

牛客网编程题——字典序题目描述 给定整数n和m, 将1到n的这n个整数按字典序排列之后, 求其中的第m个数。 对于n=11, m=4, 按字典序排列依次为1, 10, 11, 2, 3, 4, 5, 6, 7, 8, 9, 因此第4个数是2. 对于n=200, m=25, 按字典序排列依次为1 10 100 101 102 103 104 105 106 107 108 ...