dyllanzhou的专栏

Given a 2d grid map of '1's (land) and '0's (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume

Given a string S and a string T, count the number of distinct subsequences ofT in S.A subsequence of a string is a new string which is formed from the original string by deleting some (can be none

Additive number is a string whose digits can form additive sequence.A valid additive sequence should contain at least three numbers. Except for the first two numbers, each subsequent number in the s

Follow up for N-Queens problem.Now, instead outputting board configurations, return the total number of distinct solutions.class Solution {public: /*algorithm: DFS */ vectorgetNex

The n-queens puzzle is the problem of placing n queens on ann×n chessboard such that no two queens attack each other.Given an integer n, return all distinct solutions to the n-queens puzzle.Ea

Given a singly linked list where elements are sorted in ascending order, convert it to a height balanced BST./** * Definition for singly-linked list. * struct ListNode { * int val; * Lis

Given preorder and inorder traversal of a tree, construct the binary tree.Note:You may assume that duplicates do not exist in the tree./** * Definition for a binary tree node. * struct Tre

Given a binary tree and a sum, find all root-to-leaf paths where each path's sum equals the given sum.For example:Given the below binary tree and sum = 22, 5 / \

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 because12 = 4 + 4 + 4; given n = 13,

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: 1 \

Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom.For example:Given the following binary tree, 1

The set [1,2,3,…,n] contains a total of n! unique permutations.By listing and labeling all of the permutations in order,We get the following sequence (ie, for n = 3):"123""132""213""231""312""

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 number123.Find the total sum

Given inorder and postorder traversal of a tree, construct the binary tree.Note:You may assume that duplicates do not exist in the tree./** * Definition for a binary tree node. * struct Tr

Given a string s and a dictionary of words dict, determine ifs can be segmented into a space-separated sequence of one or more dictionary words.For example, givens = "leetcode",dict = ["leet",

Clone an undirected graph. Each node in the graph contains a label and a list of itsneighbors.OJ's undirected graph serialization:Nodes are labeled uniquely.We use # as a separator for each

Remove the minimum number of invalid parentheses in order to make the input string valid. Return all possible results.Note: The input string may contain letters other than the parentheses ( and).