HDU 3791 Falling Leaves 二叉搜索树  Figure 1Figure 1 shows a graphical representation of a binary tree of letters. People familiar with binary trees can skip over the definitions of a binary tree of letters, leaves of a binary tree, and a binary search tr…

题目链接:http://poj.org/problem?id=2255 思路分析:根据先序遍历(如DBACEGF)可以找出根结点(D),其后为左右子树:根据中序遍历(如ABCDEFG),已知根结点(D), 可以知道在根结点左边的为左子树结点(ABC),右边为右子树结点(EFG):可以求出左子树与右子树结点个数:已知道左右子树 结点个数(分别为3个),根据先序遍历(如DBACEGF)可知其左子树的先序遍历(BAC)与右子树的先序遍历(EGF):左右子树 的先序遍历与中序遍历可知,递归构造树再后序遍…

思路:除以2^k,找到商为奇数的位置,k为层数,有2^(k+1)-1个节点 这里直接用位运算,x & -x 就求出 2^k 了. #include<iostream> using namespace std; long lowbit(long x) { return x & -x; } int main() { long n,x; cin>>n; while(n--) { cin>>x; cout<<x-lowbit(x)+1<<…

http://poj.org/problem?id=1577 [题意] 有一颗二叉搜索树,每次操作都把二叉搜索树的叶子从左到右揪掉(露出来的父节点就变成了新的叶子结点) 先给出了揪掉的叶子序列(多个字符串) 给出这课二叉搜索树先序遍历的结果 [思路] 最后揪掉的肯定是根,最后揪掉的是最先插入的,倒着建立二叉搜索树就可以. [AC] #include<iostream> #include<cstdio> #include<cstring> #include<stri…

题目传送门 题意:输入一大堆字符串,问字典序输出每个字符串占的百分比 分析:二叉搜索树插入,然后中序遍历就是字典序,这里root 被new出来后要指向NULL,RE好几次.这题暴力sort也是可以过的... //#include <bits/stdc++.h> #include <cstdio> #include <cstring> #include <iostream> using namespace std; struct BST { char name…

思路:当时学长讲了之后,似乎有点思路----------就是倒着建一个  二叉搜索树 代码1:超时 详见超时原因 #include<iostream> #include<cstring> #include<stdio.h> using namespace std; char c[100][100]; struct node { char c; node *lchild; node *rchild; }; void f(node *p)//前序遍历输出,用递归 { pri…

二叉树(Binary Tree)是最简单的树形数据结构,然而却十分精妙.其衍生出各种算法,以致于占据了数据结构的半壁江山.STL中大名顶顶的关联容器--集合(set).映射(map)便是使用二叉树实现.由于篇幅有限,此处仅作一般介绍(如果想要完全了解二叉树以及其衍生出的各种算法,恐怕要写8~10篇). 1)二叉树(Binary Tree) 顾名思义,就是一个节点分出两个节点,称其为左右子节点:每个子节点又可以分出两个子节点,这样递归分叉,其形状很像一颗倒着的树.二叉树限制了每个节点最多有两个子节…

Serialization is the process of converting a data structure or object into a sequence of bits so that it can be stored in a file or memory buffer, or transmitted across a network connection link to be reconstructed later in the same or another comput…

Given an array of numbers, verify whether it is the correct preorder traversal sequence of a binary search tree. You may assume each number in the sequence is unique. Follow up: Could you do it using only constant space complexity? 这道题让给了我们一个一维数组,让我们…

Given a binary search tree (BST), find the lowest common ancestor (LCA) of two given nodes in the BST. According to the definition of LCA on Wikipedia: “The lowest common ancestor is defined between two nodes v and w as the lowest node in T that has…