目录

二分查找：

分块查找：（有规律模块）

分块排序：（无规律模块）

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二分查找：

import javax.swing.*;
import java.util.Scanner;

public class Binary_Search {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int[] arr = {1,2,3,4,5,6,7,8,9,10,11};
        int num = sc.nextInt();
        System.out.println(BinarySearch(arr, num));
    }

    private static int BinarySearch(int[] arr, int num) {
        int left = 0;
        int right = arr.length - 1;
        while(true){
            if(left > right){
                return -1;
            }

            int mid = (left + right) / 2;
            if(arr[mid] < num){
                left = mid + 1;
            }
            else if(arr[mid] > num){
                right = mid - 1;
            }
            else{
                return mid;
            }
        }
    }
}

分块查找：（有规律模块）

import java.util.Scanner;

public class Block_algorithm {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        //有规律的模块
        int[] arr = {16,5,9,12,21,18,
                     32,23,37,26,45,34,
                     50,48,61,52,73,66};
        
        Block b1 = new Block(21,0,5);
        Block b2 = new Block(45,6,11);
        Block b3 = new Block(73,12,17);
        
        Block[] blockArr = {b1,b2,b3};

        System.out.println("输入查找的数字:");
        int num = sc.nextInt();

        System.out.println(getindex(arr,blockArr, num));
    }

    private static int getindex(int[] arr , Block[] blockArr , int num) {
        int index = findIndexBlock(blockArr,num);
        if(index == -1)
            return -1;
        for(int i = blockArr[index].getStartindex();i <= blockArr[index].getEndindex();i++){
            if(arr[i] == num)
                return i;
        }
        return -1;
    }
    private static int findIndexBlock(Block[] blockArr , int num){
        for(int i = 0;i < blockArr.length;i++){
            if(num <= blockArr[i].getMax()){
                return i;
            }
        }
        return -1;
    }
}
//下面是标准JavaBean类，为了简洁不予展现全部
class Block{
    private int max;
    private int startindex;
    private int endindex;
    //~
}

分块查找：（无规律模块）

import java.util.Scanner;

public class Block_algorithm2 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("输入待查找的数据:");
        int num = sc.nextInt();
        //无规律模块
        int[] arr = {27,22,30,40,36,
                     13,19,16,20,
                     7,10,
                     43,50,48};
        Block2 b1 = new Block2(22,40,0,4);
        Block2 b2 = new Block2(13,20,5,8);
        Block2 b3 = new Block2(7,10,9,10);
        Block2 b4 = new Block2(43,50,11,13);
        Block2[] block2Arr = {b1,b2,b3,b4};

        System.out.println(getindex(arr, block2Arr, num));
    }

    private static int getindex(int[] arr, Block2[] block2Arr, int num) {
        int index = findIndexBlock2(block2Arr,num);
        if(index == -1)  return -1;

        for(int i = block2Arr[index].getStartindex();i <= block2Arr[index].getEndindex();i++)
        {
            if(arr[i] == num)
                return i;
        }
        return -1;
    }

    private static int findIndexBlock2(Block2[] block2Arr, int num) {
        for(int i = 0;i < block2Arr.length;i++){
            if(num >= block2Arr[i].getMin() && num <= block2Arr[i].getMax())
            {
                return i;
            }
        }
        return -1;
    }
}
//下面代码为标准JavaBean类，为了简洁就不特意展现
class Block2{
    private int min;
    private int max;
    private int startindex;
    private int endindex;
    //~
}