Just a Benginner

class Solution { public:     vector twoSum(vector &numbers, int target) {                  for(int i=0;i             for(int j=i+1;j                 if(numbers[i]+numbers[j]==target){          

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 1 \

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. # Defi

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example, Given: s1 = "aabcc", s2 = "dbbca", When s3 = "aadbbcbcac", return true. When s3 = "aadbbbaccc", retur

Given a binary tree, determine if it is a valid binary search tree (BST). Assume a BST is defined as follows: The left subtree of a node contains only nodes with keys less than the node's key.Th

public class Solution {     public boolean isScramble(String s1, String s2)     {         int n=s1.length();         boolean[][][] dp=new boolean[n][n][n+1];                  for(int i=n-1; i>=0

题目如下： Given a string S, find the longest palindromic substring in S. You may assume that the maximum length of S is 1000, and there exists one unique longest palindromic substring. 分

class Solution { public:     int lengthOfLongestSubstring(string s) {                  map stringMap;                  int i=0;         int length=0;         while(char ch=s[i]){            

/**  * Definition for singly-linked list.  * struct ListNode {  *     int val;  *     ListNode *next;  *     ListNode(int x) : val(x), next(NULL) {}  * };  */ class Solution { public:     Li

Given an integer n, generate all structurally unique BST's (binary search trees) that store values 1...n. For example, Given n = 3, your program should return all 5 unique BST's shown below. 1