你是抱着多大的觉悟说出这种话的🙄️
你只不过是一个学生，有办法背负其他人的人生吗😡
“什么都愿意做”就是这么沉重的话😡
做不来的事就别轻易说出口😡
你这个人，满脑子都只想到自己呢😒

A

easy

#include<bits/stdc++.h>
using namespace std;
#define int long long
int read()
{
	int x = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9')
	{
		if(ch == '-') f = -1;
		ch = getchar();
	}
	while(ch >= '0' && ch <= '9')
	{
		x= x * 10 + ch - '0';
		ch = getchar();
	}
	return x * f;
}

signed main()
{
	int n = read();
	if(n == 1) {
		cout << 1 << endl;
		return 0;
	} else if(n & 1) {
		cout << 1.0 * ((n / 2) + 1) / n << endl;
	} else cout << 0.5 << endl;
	return 0;
}

B

easy

#include<bits/stdc++.h>
using namespace std;
#define int long long
int read()
{
	int x = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9')
	{
		if(ch == '-') f = -1;
		ch = getchar();
	}
	while(ch >= '0' && ch <= '9')
	{
		x= x * 10 + ch - '0';
		ch = getchar();
	}
	return x * f;
}


signed main()
{
	int n = read(), k = read();
	int ans = 0;
	for(int i = 0; i < n; i++) {
		int x = read();
		if(x >= k) ans++;
	}
	cout << ans << endl;
	return 0;
}

C

easy

#include<bits/stdc++.h>
using namespace std;
#define int long long
int read()
{
	int x = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9')
	{
		if(ch == '-') f = -1;
		ch = getchar();
	}
	while(ch >= '0' && ch <= '9')
	{
		x= x * 10 + ch - '0';
		ch = getchar();
	}
	return x * f;
}

signed main() {
	int n = read();
	vector<int> a(n);
	for(int i = 1; i <= n; i++) {
		int x = read();
		a[x - 1] = i;
	};
	for(int i = 0; i < n; i++) cout << a[i] << " ";
	return 0;
}

D

求质因数个数

#include<bits/stdc++.h>
using namespace std;
#define int long long
int read()
{
	int x = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9')
	{
		if(ch == '-') f = -1;
		ch = getchar();
	}
	while(ch >= '0' && ch <= '9')
	{
		x= x * 10 + ch - '0';
		ch = getchar();
	}
	return x * f;
}

signed main() {
	int a = read(), b = read();
	int gcd = __gcd(a, b);
	int ans = 1, n = gcd;
	for(int i = 2;  i * i <= n; i++)
	{
		if(gcd % i == 0) {
			ans++;
			while(gcd % i == 0) gcd /= i;
		}
	}
	if(gcd != 1) ans++;
	cout << ans << endl;
	return 0;
}

e

状压
二进制位表示可以开的箱子
枚举每个商店，二进制数w表示钥匙可以开哪些箱子，并统计目前可以打开的个数
枚举可以到达该状态的所有状态，更新花费，即if((w | j) == w) dp[j] = min(dp[j], a);
判断有没有解
在枚举所有状态，枚举转移路径

1
2
3

for(int i = 0; i < (1 << n); i++)
			for(int j = 0; j <= i; j++)
				dp[i] = min(dp[i], dp[i ^ j] + dp[j]);

#include<bits/stdc++.h>
using namespace std;
#define int long long
int read()
{
	int x = 0, f = 1;
	char ch = getchar();
	while(ch < '0' || ch > '9')
	{
		if(ch == '-') f = -1;
		ch = getchar();
	}
	while(ch >= '0' && ch <= '9')
	{
		x= x * 10 + ch - '0';
		ch = getchar();
	}
	return x * f;
}

signed main()
{
	int n = read(), m = read();
	int tot = 0;
	vector<int> dp(1 << (n + 1) + 10, 0x3f3f3f3f);
	vector<bool> st(n + 1);
	for(int i = 0; i < m; i++)
	{
		int a = read(), b = read(), w = 0;
		for(int j = 0; j < b; j++)
		{
			int c =  read();
			w += 1 << (c - 1);
			if(!st[c]) st[c] = true, tot++;
		}
		for(int j = 0; j <= w; j++)
		{
			if((w | j) == w) dp[j] = min(dp[j], a);
		}
	}
	if(tot < n) cout << -1 << endl;
	else {
		int res = 0x3f3f3f3f;
		for(int i = 0; i < (1 << n); i++)
			for(int j = 0; j <= i; j++)
				dp[i] = min(dp[i], dp[i ^ j] + dp[j]);
		cout << dp[(1 << n) - 1] << endl;
	}
	return 0;
}