## JAVA exercise 71 - longest substring

When the uppercase and lowercase forms of each letter contained in a string s ， appear in s ， at the same time, the string s ， is called a beautiful string. For example, "abABB" is a beautiful string, because 'a' and 'a' appear at the same time, and 'B' and 'B' appear at the same time. However, "abA" is not a good string ...

Added by **googlit** on *Tue, 01 Feb 2022 22:04:27 +0200*

## Divide and conquer thought and examples

The "Divide and Conquer" in the algorithm is to divide a large problem into small problems, break them one by one, and "Divide and Conquer".
The specific operation of divide and conquer algorithm is to divide the original problem into # k # smaller subproblems and solve these # k # subproblems respectively. If the subproble ...

Added by **porko2004** on *Sat, 15 Jan 2022 10:49:10 +0200*

## java implementation and understanding of seven sorting

Insert sort
1. Insert sorting directly
Moving picture transfer gate. Thought: when playing poker, uncover the cards one by one and find the insertion position from back to front, so that the cards in your hand are always in an orderly state
// 1. Direct insertion
public static void insertSort(int[] array) {
// 1. Uncover the cards on ...

Added by **kasitzboym** on *Sun, 09 Jan 2022 04:13:50 +0200*

## Recursive divide and conquer --- example 2. Chessboard coverage

Recursive divide and Conquer - Example 2. Chessboard coverage
1, Problem description
In a chessboard composed of 2^k x 2k squares, exactly one square is incomplete. There are 2(2k) positions of incomplete squares. Therefore, there are 2^(2k) kinds of incomplete chessboard with K ≥ 0 In the problem of chessboard coverage, it is required t ...

Added by **zedan_80** on *Wed, 01 Dec 2021 00:57:27 +0200*