随笔分类 - 算法
摘要：算法分析：求树的最小最大深度时候，都有两种方法，第一种是递归思想。树最大最小深度，即为它的子树的最大最小深度+1，是动态规划的思想。还有一种方法是层序遍历树，只不过求最小深度时，找到第一个叶子节点就可以返回，该节点的深度，即为树的最小深度。求最大深度时，需要层序遍历完整棵树。
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摘要：算法分析：递归和非递归两种方法。
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摘要：第一种也是最常用的一种，使用queue。还有一种不使用queue的方法。不使用queue的思路，其实就是每次都只存储一层的节点，然后遍历这一层的节点，是真正的按层遍历的思想。每次遍历的都是当前层，记录的都是当前层的下一层。
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摘要：问题描述： Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next leve
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摘要：问题描述： Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example:Given binary t
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摘要：问题描述： Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center). For example, this binary tree [1,2,2,3,4,4,3] is
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摘要：算法分析：这道题很简单，利用递归即可。
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摘要：问题描述：题意就是二叉树中有两个节点交换了，恢复结构。 Two elements of a binary search tree (BST) are swapped by mistake. Recover the tree without changing its structure. 算法分析：其
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摘要：算法分析：两种方法，一种是中序遍历，然后得到一个序列，看序列是否是有序的。第二种，是用递归。 中序遍历： 递归：
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摘要：问题描述： 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
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摘要：Unique Binary Search Trees：求生成二叉排序树的个数。 Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example,Given n
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摘要：问题描述： Given a string containing only digits, restore it by returning all possible valid IP address combinations. For example:Given "25525511135", retu
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摘要：ReverseLinkedList： ReverseLinkedList2: 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->NU
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摘要：问题描述： A message containing letters from A-Z is being encoded to numbers using the following mapping: Given an encoded message containing digits, deter
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摘要：问题描述： The gray code is a binary numeral system where two successive values differ in only one bit. Given a non-negative integer n representing the tot
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摘要：问题描述： Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively. Below is one possible repres
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摘要：/* w代表物品重量，v代表物品价值，c代表背包最大能容纳重量 res[i][j]代表背包可以选择前i个物品，最大容量为j时候的最大价值 res[i-1][j] if(w[i-1] > j) res[i][j] = max((res[i-1][j-w[i-1]]+v[i-1]), res[i-1][j]) else **/ public c...
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摘要：问题描述： Given a linked list and a value x, partition it such that all nodes less than x come before nodes greater than or equal to x. You should preserv
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摘要：问题描述： Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area. For example, given the fol
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摘要：问题描述： Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in th
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