张小小Angela-CSDN博客

原创 Matlab生成归一化直方图

使用matlab的函数histogram可以直接得到数据的直方图，但这并不是归一化的直方图。使用如下代码可以得到归一化的直方图x = randn(10000, 1);numOfBins = 100;[histFreq, histXout] = hist(x, numOfBins);binWidth = histXout(2)-histXout(1);figure;bar(histXout,

2016-03-31 18:23:53 19102 1

原创 Matlab读写TIFF格式文件

t = Tiff(‘myfile2.tif’,’w’); tagstruct.ImageLength = size(nmf,1) tagstruct.ImageWidth = size(nmf,2) tagstruct.Photometric = 1 tagstruct.BitsPerSample = 32 tagstruct.SamplesPerPixel = 4 tagstruct

2016-03-04 21:41:48 51572 4

1. 骑摩托车旅游和其他的方式完全不同。坐在汽车里，你只是被局限在一个小空间之内，因为已经习惯了，你意识不到从车窗向外看风景和看电视差不多。你只个被动的观众，景物只能呆板地从窗外飞驰而过。骑摩托车可就不同了。它没有什么车窗玻璃在面前阻挡你视野，你会感到自己和大自然紧密地结合在了一起。你就处在景致之中，而不再是观众，你能感受到那种身临其境的震撼。脚下飞驰而过的是实实在在的水泥公路，和你走过的土地没有

2015-11-14 16:08:52 2465

原创 LeetCode(55) Search Insert Position

题目描述Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You may assume no duplicates in the array.H

2015-09-23 21:00:23 617

原创 LeetCode (54) Valid Anagram

题目描述Given two strings s and t, write a function to determine if t is an anagram of s.For example, s = “anagram”, t = “nagaram”, return true. s = “rat”, t = “car”, return false.Note: You may assume t

2015-09-23 19:42:19 610

原创 LeetCode(53) Climbing Stairs (剑指Offer->跳台阶、变态跳台阶)

Climbing Stairs (跳台阶)题目描述You are climbing a stair case. It takes n steps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?本题对应了《剑指offe

2015-09-23 19:38:44 1766

原创 LeetCode(52) Power of Two

题目描述Given an integer, write a function to determine if it is a power of two.判断一个数是否是2的指数。题目解答本题很简单可以通过位运算进行判断。首先如果一个数为负，则肯定不为2的指数，直接返回false；对于正数可以判断该数字二进制表达时1的个数，如果1的个数为只有一个则为2的指数，否则不为2的指数。class Soluti

2015-09-23 19:21:16 669

原创 LeetCode(51) Symmetric Tree

题目描述Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree is symmetric:But the following is not:判断一棵二叉树是否对称。解题思路根据题目要求，可以认为是树的层序遍历的

2015-09-23 18:58:18 455

原创 LeetCode(50) Binary Tree Inorder Traversal 中序遍历

题目描述Given a binary tree, return the inorder traversal of its nodes’ values.For example: Given binary tree {1,#,2,3},return [1,3,2].解题思路之前在二叉树的先序遍历中已经介绍了二叉树遍历的思路了，这里直接上代码。递归解法/** * Definition for a bi

2015-09-23 18:50:53 449

原创 LeetCode(49) Populating Next Right Pointers in Each Node I II

Populating Next Right Pointers in Each Node I题目描述Given a binary treestruct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next;}Populate each next pointer to point to i

2015-09-23 18:45:56 571

原创 LeetCode(48) Binary Tree Preorder Traversal

题目描述Given a binary tree, return the preorder traversal of its nodes’ values.For example: Given binary tree {1,#,2,3}, return [1,2,3].本题要求对二叉树进行先序遍历，所谓先序遍历：根-左-右，先遍历根结点，再遍历左子树，最后遍历右子树。递归求解二叉树的遍历最简单的

2015-09-23 18:24:14 507

原创 LeetCode(47) Invert Binary Tree

题目描述Invert a binary tree. => 题目要求将二叉树的左右子树进行逆转。解题思路根据题目的要求可以进行一层一层的逆转，也就是交换结点的左右子树。将未处理的元素放入栈中，本题的关键在于对于元素的入栈顺序进行控制。/** * Definition for a binary tree node. * struct TreeNode { * int val; *

2015-09-23 18:11:22 428

原创 LeetCode(46) Lowest Common Ancestor of a Binary （Search） Tree

Lowest Common Ancestor of a Binary Search Tree题目描述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:

2015-09-23 16:11:22 505

原创 LeetCode(45) Simplify Path

题目描述Given an absolute path for a file (Unix-style), simplify it.For example, path = “/home/”, => “/home” path = “/a/./b/../../c/”, => “/c”本题要求对给定的Unix路径进行简化，关键点在于理解Unix路径的规则以及对一些边界条件要加以考虑。Unix路径规则：

2015-09-23 15:20:54 581

原创 LeetCode(44) Best Time to Buy and Sell Stock I II

Best Time to Buy and Sell Stock I题目描述Say you have an array for which the ith element is the price of a given stock on day i.If you were only permitted to complete at most one transaction (ie, buy one a

2015-09-23 14:55:59 447

原创 LeetCode(43) Add Digits

题目描述Given a non-negative integer num, repeatedly add all its digits until the result has only one digit.For example:Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has only one digi

2015-09-23 11:22:10 598

原创 LeetCode(42) Maximum Depth of Binary Tree

题目描述Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.题目要求计算一棵二叉树的高度。本题最简单的解法是递归计算左右子树的高度，并在左

2015-09-23 10:59:19 541

原创 LeetCode(41) Single Number I 和 II

题目描述Given an array of integers, every element appears twice except for one. Find that single one.如果一个给定数组中除了一个元素其他所有元素均出现了两次，这里让我们找到只出现了一次的元素。解题方法这里需要使用位运算来解决本题。我们知道异或运算有这样的结果a^a = 0，所以对数组中所有元素进行异或运算时，

2015-09-23 10:48:26 466

原创 LeetCode(40) Median of Two Sorted Arrays (两排序数组中位数)

题目描述There are two sorted arrays nums1 and nums2 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)).题目要求寻找两个已排序数组的中位数解题代码本题我使用

2015-09-22 21:18:45 1810

原创 LeetCode (39) Ugly Number I II (丑数)

Ugly Number I 和 Ugly Number II

2015-09-22 21:12:32 1559

原创 LeetCode(38) Delete Node in a Linked List

题目描述Write a function to delete a node (except the tail) in a singly linked list, given only access to that node.Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node with value

2015-09-22 20:57:00 447

原创 LeetCode(37) Contain Duplicates I II

共有两道与重复数字相关的题目，contain duplicates I 和 II。Contain Duplicates I题目描述Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least tw

2015-09-22 20:50:37 475

原创 LeetCode (35) Isomorphic Strings

题目描述Given two strings s and t, determine if they are isomorphic.Two strings are isomorphic if the characters in s can be replaced to get t.All occurrences of a character must be replaced with another c

2015-05-07 15:03:57 1426

原创 LeetCode (34) Reverse Linked List

题目描述Reverse a singly linked list.例如： 1 -> 2 -> 3 -> 4 -> 5 -> 6 ==> 6 -> 5 -> 4 -> 3 -> 2 -> 1本题比较简单，使用两个指针，一个指针（p）表示前一个结点，另一个（l）表示当前结点。主要指针操作如下：ListNode* t = l -> next; // next of current nodel -> n

2015-05-07 14:57:48 2040

原创 LeetCode (33) Longest Substring Without Repeating Characters

题目描述Given a string, find the length of the longest substring without repeating characters.For example, the longest substring without repeating letters for “abcabcbb” is “abc”, which the length is 3.

2015-05-07 14:49:53 961

原创 LeetCode (32) Add Two Numbers (字符串)

题目描述You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a l

2015-05-07 14:26:59 454

原创 LeetCode (31) Divide two integers (不使用 *, /, mod 求两个数相除结果)

题目描述Divide two integers without using multiplication, division and mod operator.If it is overflow, return MAX_INT.对两个数 dividend 和 divisor，在不使用乘法、除法、取余操作求它们的相除结果，最直观的做法就是反复对 dividend - divisor 进行计数，直到差小

2015-05-07 14:13:23 578

原创 LeetCode (30) Palindrome Number (回文数字)

题目描述Determine whether an integer is a palindrome. Do this without extra space.Some hints: Could negative integers be palindromes? (ie, -1) —— 负数不为回文If you are thinking of converting the integer to s

2015-05-07 13:51:45 1139

原创 LeetCode (29) Fraction to Recurring Decimal

题目描述Given two integers representing the numerator and denominator of a fraction, return the fraction in string format.If the fractional part is repeating, enclose the repeating part in parentheses.For

2015-05-07 13:34:03 567

原创 Leetcode (28) Longest Consecutive Sequence

Given an unsorted array of integers, find the length of the longest consecutive elements sequence.For example, Given [100, 4, 200, 1, 3, 2], The longest consecutive elements sequence is [1, 2, 3, 4].

2015-04-28 14:46:16 571

原创 LeetCode (27) Linked List Cycle (判断cycle存在、寻找cycle入口节点)

判断cycle存在Given a linked list, determine if it has a cycle in it.Follow up: Can you solve it without using extra space?本题要求判断给定链表中是否存在循环。并且题目要求不要使用extra space，因此，我们就不能保存每一个结点的value，在遍历的时候判断是否是循环。这道题可以通过

2015-04-28 14:36:06 1653

原创 LeetCode (26) LRU Cache

题目描述Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations: get and set.get(key) - Get the value (will always be positive) of the key if t

2015-04-26 11:50:56 928 2

原创 LeetCode (25) Reverse Nodes in k-Group (链表)

题目描述Given a linked list, reverse the nodes of a linked list k at a time and return its modified list.If the number of nodes is not a multiple of k then left-out nodes in the end should remain as it is.

2015-04-26 11:29:00 857

原创 LeetCode (24) Happy Number

题目描述Write an algorithm to determine if a number is “happy”.A happy number is a number defined by the following process: Starting with any positive integer, replace the number by the sum of the squares

2015-04-26 10:59:17 12535

原创 OpenCV保存成XML（FileStorage）和CSV（重载<<运算符）文件

XML文件（使用FileStorage类）使用OpenCV时不仅要保存影像结果，往往也需要保存中间的矩阵结果，而OpenCV的imwrite函数只支持CV8U类型的数据（使用OpenCV保存其他类型Mat的时候，程序不会报错，但是无法生成结果文件），因此会给工作带来很多不便。OpenCV在2.0以后的版本中提供了FileStorage类，供用户直接使用，保存为XML/YAML文件。保存XML保存示例

2015-04-25 21:24:49 8546 7

原创 LeetCode (23) Jump Game （动态规划）

题目描述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.Determine if you

2015-04-24 20:20:42 1986 1

原创 LeetCode (22) Word Search

题目描述Given a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell, where “adjacent” cells are those horizontally or vertically

2015-04-22 16:18:41 804

原创 LeetCode (21) Find Minimum in Rotated Sorted Array （with/without duplicates）

题目描述Suppose a sorted array is rotated at some pivot unknown to you beforehand.(i.e., 0 1 2 4 5 6 7 might become 4 5 6 7 0 1 2).Find the minimum element.这里需要理解一个概念什么为Rotated Sorted Array。根据题目描述，Rotated

2015-04-22 16:03:13 696

原创 LeetCode (20) house robber （数组不相邻元素最大值）

题目描述You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed, the only constraint stopping you from robbing each of them is that adjacent ho

2015-04-22 15:48:51 3670

原创 LeetCode (19) Multiply Strings

题目描述Given two numbers represented as strings, return multiplication of the numbers as a string.Note: The numbers can be arbitrarily large and are non-negative.对两组非负数字进行相乘，使用数组表示数字，且题目中说明数组很大，因此，因此不能直接将

2015-04-22 15:39:25 836

模式识别 K均值

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