c++生成随机数

产生随机数的叫随机数生发器

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生成随机数

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const unsigned zseed=time(0);


void solve()
{
	//随机数生发器
	mt19937_64 m{zseed};
	//种子
	rep(i,1,5)
	cout<<m()<<endl;
	return;
}

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重排序列

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const unsigned zseed=time(0);
mt19937_64 zgen{zseed};

void solve()
{
	vector<int>a={1,2,3,4,5,6};
	shuffle(begin(a),end(a),zgen);
	for(auto i:a)	cout<<i<<' ';
	cout<<endl;
	return;
}

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产生范围内均匀分布的整数随机数

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const unsigned zseed=time(0);
mt19937_64 zgen{zseed};

struct UI{
	//随机数的分布器
	//产生随机数的区间是[a,b]
	uniform_int_distribution<int>u;	
	//随机数的生发器
	mt19937_64& gen{zgen};
	int get()
	{
		return u(gen);
	}
	UI(int a=0,int b=1):u(a,b){};
};

void solve()
{
	UI u{-2,2};
	rep(i,1,5)	cout<<u.get()<<endl;
	return;
}

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产生范围内均匀分布的小数

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左闭右开$[)$

const unsigned zseed=time(0);
mt19937_64 zgen{zseed};

struct UD{
	uniform_real_distribution<db>u;
	mt19937_64& gen{zgen};
	db get()
	{
		return u(gen);
	}
	UD(db a=0,db b=1)	:u{a,b}{}	
};