C++ 实现位图

Posted 2021-06-04 Wecccccccc

代码如下:

#include <iostream>
#include <vector>
using namespace std;

class BitMap
{
public:

	BitMap(size_t range):_bit(range/32+1){}

	void set(const size_t num)
	{
		int idx = num / 32;//idx 数组下标

		int bitIdx = num % 32;

		_bit[idx] |= 1 << bitIdx;
	}

	bool find(const size_t num)
	{
		int idx = num / 32;
		int bitIdx = num % 32;
		return (_bit[idx] >> bitIdx) & 1;
	}

	void reset(const size_t num)
	{
		int idx = num / 32;
		int bitIdx = num % 32;
		_bit[idx] &= ~(1 << bitIdx);
	}


private:
	vector<int>_bit;
};

int main()
{
	BitMap m(1000);
	m.set(233);
	if (m.find(233)) cout << "yes" << endl;
	else cout << "no" << endl;

	m.reset(233);
	if (m.find(233))cout << "yes" << endl;
	else cout << "no" << endl;

	if (m.find(2))cout << "yes" << endl;
	else cout << "no" << endl;

	return 0;
}

测试结果: