BitSet

相关博客

https://blog.csdn.net/weixin_43067762/article/details/105637469
https://my.oschina.net/cloudcoder/blog/294810

自己整理的api

package com.crayon2f.algorithm.bit;
import org.junit.Test;
import java.util.BitSet;
/**
 * Created by feifan.gou@gmail.com on 2021/7/28 18:09.
 */
public class BitSetLearn {
    @Test
    //设置方法
    public void set() {
        BitSet bitSet = new BitSet();
        //设置某个值为true（有）
        bitSet.set(1); //{1}
        //设置一个范围为true
        bitSet.set(1, 10); //{1, 2, 3, 4, 5, 6, 7, 8, 9}
        //设置一个值为boolean
        bitSet.set(1, false); //{2, 3, 4, 5, 6, 7, 8, 9}
        //设置一个范围为boolean
        bitSet.set(1, 10, false);//{}
    }
    @Test
    public void get() {
//
        BitSet bitSet = new BitSet();
        bitSet.set(1, 11); //{1,2,3,4,5,6,7,8,9,10}
        //获取指定索引是否有值
        System.out.println(bitSet.get(2));
        //获取范围
        BitSet bitSet1 = bitSet.get(0, 2);
        System.out.println(bitSet1.get(3));
    }
    @Test
    public void clear() {
        BitSet bitSet = new BitSet();
        bitSet.set(1, 11); //{1,2,3,4,5,6,7,8,9,10}
        //去除指定位置
        bitSet.clear(2);
        //去除范围
        bitSet.clear(3,6);
        //去除所有
//        bitSet.clear();
    }
    @Test
    public void search() {
        BitSet bitSet = new BitSet();
        bitSet.set(1, 11); //{1,2,3,4,5,6,7,8,9,10}
        //从X开始查找下一个为false的位置
        System.out.println(bitSet.nextClearBit(5)); // 11
        //从X开始查找上一个为false的位置
        System.out.println(bitSet.previousClearBit(5)); //0
        bitSet.clear();
        bitSet.set(2,5); //{2,3,4}
        bitSet.set(6,10); //{2,3,4,6,7,8,9}
        //从X开始下一个为true的位置
        System.out.println(bitSet.nextSetBit(0)); //2
        System.out.println(bitSet.nextSetBit(5)); //6
        //从X开始上一个为true的位置
        System.out.println(bitSet.previousSetBit(10)); //9
        System.out.println(bitSet.previousSetBit(5)); //4
        System.out.println(bitSet.cardinality());
    }
    @Test
    public void normal() {
        BitSet bitSet = new BitSet();
        bitSet.set(1, 11); //{1,2,3,4,5,6,7,8,9,10}
        //值为 true的数量
        System.out.println(bitSet.cardinality()); //10
        BitSet bitSet1 = new BitSet();
        bitSet1.set(5,11); //{5, 6, 7, 8, 9, 10}
        //求交集
        bitSet.and(bitSet1);
        System.out.println(bitSet); //{5, 6, 7, 8, 9, 10}
        BitSet bitSet2 = new BitSet();
        bitSet2.set(20, 30);
        //求并集
        bitSet1.or(bitSet2);
        System.out.println(bitSet1); //{5, 6, 7, 8, 9, 10, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29}
        BitSet bitSet3 = new BitSet();
        bitSet3.set(23);
        bitSet3.set(24);//{23,24}
        //剔除交集部分
        bitSet2.andNot(bitSet3);
        System.out.println(bitSet2); //{20, 21, 22, 25, 26, 27, 28, 29}
        BitSet bitSet4 = new BitSet();
        bitSet4.set(24);
        bitSet4.set(25); //{24,25}
        //并集后去除交集
        bitSet3.xor(bitSet4);
        System.out.println(bitSet3);
        //给某个位置取反
        bitSet4.flip(23);
        //给某个范围取反
        bitSet4.flip(22,24);
        System.out.println(bitSet4);
    }
}