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catalogue Introduction to HashMap differences from other containers Introduction to HashMap The difference between HashMap and Hashtable Different parent class Null value problem Thread safety Different traversal modes Different initial capacity Hash values are calculated differently Differences between HashMap and HashSet Difference ...

Linear Table 1. Definition of Linear Table A linear table is a finite sequence of n(n < 0) data elements of the same data type, where n is the table length, and a linear table is an empty table when n=0. If a linear table is named L, it is generally expressed as L = ...

The foundation is weak and the understanding is still shallow. If there are mistakes, please correct them. Linear list single chain list (Ⅲ) Various basic operations of headless node and headless node in single linked list (complete code) Node with head #include<stdio.h> #include<malloc. h> / / this header file is required when o ...

Indexing principle and slow query optimization 1. What is an index? Index is a data structure in the storage engine, or the organization of data, also known as key. It is a data structure used by the storage engine to quickly find records. Building an index for data is like building a directory for a book, or creating a phonetic order ...

Prepare for the second test, three questions a day Topic 1: incremental ternary subsequence (leetcode 1.12 daily) Give you an integer array nums to judge whether there is an increasing subsequence with length of 3 in this array. If such a triple subscript (i, j, k) exists and I < J < K is satisfied, so that num [i] < num [J] < nu ...

1. Analyze the characteristics of elements in binary sort tree The binary sort tree must ensure that the elements can be compared in size How to ensure that elements can be compared in size? Implement comparator interface - implement the Comparable interface and rewrite the compareTo method -- internal comparator - implement Comparator int ...

Chapter VI decorator mode The behavior of class or its algorithm can be changed at run time, which belongs to behavioral mode Application: different implementation classes have different functions, one policy structure, one context class (interface parameters) and n interface implementation classes public class StrategyPatternDemo { public ...

HashMap first appeared in JDK 1.2, and the underlying implementation is based on hash algorithm. HashMap allows null keys and null values. When calculating the hash value of HA key, the hash value of null key is 0. HashMap does not guarantee the order of key value pairs, which means that the order of key value pairs may change after some operat ...

0. Preface The brushing algorithm clocked in for the sixth day and today picked up a moderate problem. But with the precipitation knowledge of the previous problem solving, it doesn't feel too painful to solve today. But there is something new to settle, so this is a record. That's how the brushing algorithm works. It's okay in general ...

Data structure and algorithm 1. Basic knowledge 1. Relationship between data Logical structure: it refers to the relationship between data elements, which is imagined by us and is not substantially stored in the computer. ​ Linear structure: there is a one-to-one relationship between data elements in a linear structure Tree structure: the ...