minGW_Lee on the way

单链表总结：首先就是指针的问题，就算new出新指针tmp做临时变量，对tmp的改变会同时改掉原指针，因为它们本身指向同一内存地址。所以对链表的操作，一定要注意指针的操作顺序。对链表的逆序，注意添加头结点，会是操作方便很多nlogn的排序有快速排序、归并排序、堆排序。 双向链表用快排比较适合，堆排序也可以用于链表，单向链表适合用归并排序技巧：添加头指针，再进行操作，更加方便。使用快慢指针

Given a string, your task is to count how many palindromic substrings in this string. The substrings with different start indexes or end indexes are counted as different substrings even they consist

You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not need to start or end at the root or a leaf, but it

Given a non-empty array containing only positive integers, find if the array can be partitioned into two subsets such that the sum of elements in both subsets is equal. Note: Each of the array el

题目链接：https://leetcode.com/problems/remove-invalid-parentheses/ Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results.Note: The input str

Given an array of integers and an integer k, you need to find the total number of continuous subarrays whose sum equals to k.Example 1:Input:nums = [1,1,1], k = 2Output: 2Note: The length of the ar

题目：Given n non-negative integers a1, a2, …, an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two

Given an unsorted integer array, find the first missing positive integer. For example, Given [1,2,0] return 3, and [3,4,-1,1] return 2. Your algorithm should run in O(n) time and uses const

JumpGame 1 Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position.

LeetCode 笔记系列 17 Largest Rectangle in HistogramLeetCode 笔记系列 18 Maximal Rectangle [学以致用]

Given a string S and a string T, find the minimum window in S which will contain all the characters in T in complexity O(n). For example, S =”ADOBECODEBANC” T =”ABC” Minimum window is”BANC”

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], [1,3], [1,4],] 解析：首先我

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 satisfy

There are two sorted arrays A and B of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)).难点：需要在O(log (m+n))内完成。//采用数组合并的思想,然后取

A 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. Subscribe to see which companie

Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. Subscribe to see which companies asked this question. 解题思路： 要给k个顺序单链表排序，我们熟知合并两个顺序单链表的操作。但是

递归的思想：个人感觉先写递归表达式，想象最后一层的情况，思考跳出的条件。合并两个顺序表： public ListNode mergeTwoLists(ListNode l1,ListNode l2) { if (l1 == null) return l2; if (l2 == null) return l

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 = 13, re

题目:Say you have an array for which the i-th element is the price of a given stock on day i.Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, bu