位图——使用long类型表示0~63数字

前言：

        本文主要参考左神讲解位图视频做的笔记，仅供大家参考。

代码：

import java.util.HashSet;
 
public class BitMap2 {
 
	
	public static class BitMap {
 
		private long[] bits;
 
		public BitMap(int max) {
			bits = new long[(max + 64) >> 6];
		}
 
		public void add(int num) {
			bits[num >> 6] |= (1L << (num & 63));
		}
 
		public void delete(int num) {
			bits[num >> 6] &= ~(1L << (num & 63));
		}
 
		public boolean contains(int num) {
			return (bits[num >> 6] & (1L << (num & 63))) != 0;
		}
 
	}
 
	public static void main(String[] args) {
		System.out.println("测试开始！");
		int max = 10000;
		BitMap bitMap = new BitMap(max);
		HashSet set = new HashSet<>();
		int testTime = 10000000;
		for (int i = 0; i < testTime; i++) {
			int num = (int) (Math.random() * (max + 1));
			double decide = Math.random();
			if (decide < 0.333) {
				bitMap.add(num);
				set.add(num);
			} else if (decide < 0.666) {
				bitMap.delete(num);
				set.remove(num);
			} else {
				if (bitMap.contains(num) != set.contains(num)) {
					System.out.println("Oops!");
					break;
				}
			}
		}
		for (int num = 0; num <= max; num++) {
			if (bitMap.contains(num) != set.contains(num)) {
				System.out.println("Oops!");
			}
		}
		System.out.println("测试结束！");
	}
 
}