bu_min的博客

题目描述：Given two strings s and t, determine if they are isomorphic.Two strings are isomorphic if the characters in s can be replaced to get t.All occurrences of a character must be replaced with a

题目描述:Given a m x n grid filled with non-negative numbers, find a path from top left to bottom right which minimizes the sum of all numbers along its path.Note: You can only move either down or r

题目描述：Find the contiguous subarray within an array (containing at least one number) which has the largest product.For example, given the array [2,3,-2,4],the contiguous subarray [2,3] has the lar

题目描述：Follow up for "Unique Paths":Now consider if some obstacles are added to the grids. How many unique paths would there be?An obstacle and empty space is marked as 1 and 0 respectivel

题目描述：Suppose a sorted array is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).You are given a target value to search. If found in the array re

题目描述：Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would hav

题目描述：Note: This is an extension of House Robber.After robbing those houses on that street, the thief has found himself a new place for his thievery so that he will not get too much attention. Th

题目描述：Given a set of distinct integers, nums, return all possible subsets.Note:Elements in a subset must be in non-descending order.The solution set must not contain duplicate subsets.For exa

Given an array of integers, find two numbers such that they add up to a specific target number.The function twoSum should return indices of the two numbers such that they add up to the target, where

题目描述：Implement pow(x, n).Hide Tags Math Binary Search分析：C++库中有pow(double x,int y),但是只针对指数为非负的。因此本题只需特殊考虑参数为负数的情况。方法一：1. 当指数为0时，幂为1；2. 当指数为正数时，结果为pow（）；3. 当指数为负数时，结果为pow()的倒数备注：在考虑第

题目描述：A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).The robot can only move either down or right at any point in time. The robot is trying to r

题目描述：You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjac

已知某公司有n个食堂，第i个食堂有m[i]种食物（1(注意，该员工有个挑食的特点，同一种食物他最多点一份。)现告诉你所有食堂食物的信息，希望你进行选择搭配，使得该员工获得最大享受度，并输出这个享受度的值。Input第一行是一个正整数T（1对于每组数据——第一行是三个数n,bot,top,n 代表食堂数目,n属于[1,10],bot和top分别是是这次

题目描述：Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.)You have the following 3 operations permitted on a

题目描述：Given a binary tree    struct TreeLinkNode {      TreeLinkNode *left;      TreeLinkNode *right;      TreeLinkNode *next;    };Populate each next pointer to point to its next rig

题目描述：Given n, how many structurally unique BST's (binary search trees) that store values 1...n?For example,Given n = 3, there are a total of 5 unique BST's.   1         3     3      2

题目描述：Given an array where elements are sorted in ascending order, convert it to a height balanced BST.Hide Tags Tree Depth-first Search分析：要构造平衡的二叉搜索树（AVL），必须满足平衡条件：它是一棵空树或它的左右两个子树的高度差的绝对值不超过

题目描述：Follow up for problem "Populating Next Right Pointers in Each Node".What if the given tree could be any binary tree? Would your previous solution still work?Note:You may only use consta

题目描述：Given a 2D binary matrix filled with 0's and 1's, find the largest square containing all 1's and return its area.For example, given the following matrix:1 0 1 0 01 0 1 1 11 1 1 1 11 0

题目描述：Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses.For example, given n = 3, a solution set is:"((()))", "(()())", "(())()", "()(())"

题目描述：Given a sorted integer array without duplicates, return the summary of its ranges.For example, given [0,1,2,4,5,7], return ["0->2","4->5","7"].Credits:Special thanks to @jianchao.li.fight

题目描述：Implement a basic calculator to evaluate a simple expression string.The expression string contains only non-negative integers, +, -, *, / operators and empty spaces . The integer division sho

题目描述：Implement atoi to convert a string to an integer.Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible inp

题目描述：Given an array of n positive integers and a positive integer s, find the minimal length of a subarray of which the sum ≥ s. If there isn't one, return 0 instead.For example, given the array [

题目描述：Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number.An example is the root-to-leaf path 1->2->3 which represents the number 123.Find the tot

题目描述:Sort a linked list using insertion sort.Hide Tags Linked List Sort分析：插入排序是在一个已排序的序列中找到当前元素正确的位置，然后插入禁区即可。由于链表不能随机访问，所以每处理一个元素时，都必须从前往后找到正确的位置，然后插入节点即可。为了方便操作，可以新建一个带有头节点的链表new

题目描述：Invert a binary tree.     4   /   \  2     7 / \   / \1   3 6   9to     4   /   \  7     2 / \   / \9   6 3   1Trivia:This problem was inspired by this origi

题目描述：Given a range [m, n] where 0 For example, given the range [5, 7], you should return 4.Credits:Special thanks to @amrsaqr for adding this problem and creating all test cases.Hide Tag

题目描述：Given a binary tree, flatten it to a linked list in-place.For example,Given         1        / \       2   5      / \   \     3   4   6The flattened tree should look like: 

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.For example,Given nums = [0, 1, 3] return 2.Note:Your algorithm should ru

There are N gas stations along a circular route, where the amount of gas at station i is gas[i].You have a car with an unlimited gas tank and it costs cost[i] of gas to travel from station i to it

Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i].Solve it without division and in O(n

Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ...) which sum to n.For example, given n = 12, return 3 because 12 = 4 + 4 + 4; given n =

题目描述 :Sort a linked list in O(n log n) time using constant space complexity.Hide Tags Linked List Sort分析：上一题是用插入排序，时间复杂度是O(N^2),这一题要求的时间复杂度只能是快排，归并，或堆。对于数组来讲，这三个算法都是比较容易实现，但是对于链表，快排不太适合，因为每次只将

题目描述：Given two integers n and k, return all possible combinations of k numbers out of 1 ... n.For example,If n = 4 and k = 2, a solution is:[  [2,4],  [3,4],  [2,3],  [1,2],  [1,

题目描述：Follow up for "Remove Duplicates":What if duplicates are allowed at most twice?For example,Given sorted array nums = [1,1,1,2,2,3],Your function should return length = 5, with the f

题目描述：Find the total area covered by two rectilinear rectangles in a 2D plane.Each rectangle is defined by its bottom left corner and top right corner as shown in the figure.Rectangle AreaA

题目描述：Given a complete binary tree, count the number of nodes.Definition of a complete binary tree from Wikipedia:In a complete binary tree every level, except possibly the last, is completely

题目描述：Implement a basic calculator to evaluate a simple expression string.The expression string may contain open ( and closing parentheses ), the plus + or minus sign -, non-negative integers and 

题目描述：Reverse a linked list from position m to n. Do it in-place and in one-pass.For example:Given 1->2->3->4->5->NULL, m = 2 and n = 4,return 1->4->3->2->5->NULL.Note:Given m, n satisf