Programmer Think

Daily question 611: judge whether it is a triangle My inherent impression is to use violence to solve, then timeout, and then sort the array and recalculate. It is passed, but it takes too long. class Solution { public int triangleNumber(int[] nums) { int n = nums.length; if(n<3) return 0; int count = 0; ...

String class String classes mainly refer to string, StringBuffer and StringBuilder. As can be seen from the source code comments, both string and StringBuffer are jdk1 0, and StringBuilder is jdk1 5. Generally speaking, the most commonly used is String, which is immutable, followed by variable StringBuilder and StringBuffer. StringBuffer is th ...

1, Title [LeetCode-242] Given two strings s and t, write a function to determine whether t is an alphabetic ectopic word of s. Note: if each character in ， s and t ， occurs the same number of times, then ， s and t ， are called alphabetic words. Example 1: Input: s = "anagram", t = "nagaram" Output: true Exa ...

People who learn Java get more or less the message that String is immutable. So is that true? Pre-knowledge of this article: Reflection, jmm. 1. How to change a String Open the source of the String and you can see that the data of the String object is stored in its value array. In the early version of Java, this is an array of type char[], r ...

This div2 mainly focuses on the derivation of the formula and the optimization of time complexity. This requires us to be sensitive to some digital patterns in life. The topic gives us a lot of hints, such as the amount of data in 1e5. If we adopt the method of pairing one by one, the time complexity will timeout. Considering the nesting of va ...

Dictionary tree (prefix tree) summary: The dictionary tree (Trie) is used to determine whether a string exists or has a string prefix. Why do we need a dictionary tree to solve this kind of problem? If we have a dictionary that stores nearly 10000 words, even if we use hash, the actual cost of searching for a word in it is very lar ...

The object of String is immutable, StringBuffer and The object of StringBuilder is variable, and StringBuilder is an improved class of StringBuilder. The methods of the two are similar. Therefore, we mainly record the methods in learning String and stringbuild classes.     Methods in String 1.intern() translation address There are no ...

Hello, everyone. I'm surprised. Let's talk about string today. There are many scenarios for using strings, which are used in human-computer interaction and dual computer communication. For example: Send instructions to MCU through serial port to perform operation or configure parameters.MCU reads sensor data, and the data format is string. Gen ...

subject Problem description Please write a command line analyzer to analyze which options are included in a given command line. Each command line consists of several strings separated by exactly one space. The first of these strings is the name of the command-line tool, which is composed of lowercase letters. Your program does not need ...

1: Title Sina Weibo can embed "topic" in the speech, that is, the topic text in the speech can be written between a pair of "#" to generate a topic link. Click the link to see how many people are discussing the same or similar topics with themselves. Sina Weibo will also update the list of hot topics at any time, and put t ...