CF 937

A

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-8;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
//const int maxn = 3e5 + 10;
const int  maxm = ;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
ll mod = 3e7;
int num[];
int main()
{
        int n;
        cin >> n;
        int cur;
        for (int i = ; i <= n; i++)
        {
                cin >> cur;
                num[cur] = ;
        }
        int anser = ;
        for (int i = ; i <= ; i++)
        {
                if (num[i])
                {
                        anser++;
                }
        }
        cout << anser << endl;
        return ;

}

B

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-8;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
//const int maxn = 3e5 + 10;
const int  maxm = ;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
ll mod = 3e7;
ll p, y;
bool check(ll now)
{
        for (int i = ; i * i <= now && i <= p; i++)
        {
                if (now % i == )
                {
                        return ;
                }
        }
        return ;
}
int main()
{
        cin >> p >> y;
        int flag = ;
        for (int i = y; i >= p + ; i--)
        {
                if (check(i))
                {
                        cout << i << endl;
                        flag = ;
                        break;
                }
        }
        if (!flag)
        {
                cout << - << endl;
        }
        return ;
}

C

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-10;
const double EPS = 1.0e-4;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
int main()
{
        double k, d, t;
        cin >> k >> d >> t;
        ll k1 = k;
        ll d1 = d;
        double ans = ;
        if (k1 % d1 == )
        {
                printf("%.1f\n", t);
                return ;
        }
        else
        {
                double bei = (long long)(k / d) + 1.0;
                //printf("bei: %.1f\n", bei);
                double xunhuan = bei * d;
                //printf("xunhuan: %.1f\n", xunhuan);
                double ximie = xunhuan - k;
                //printf("ximie: %.1f\n", ximie);
                double once = k + ximie / 2.0;
                //printf("once: %.1f\n", once);
                double bei2 = (long long)(t / once);
                //printf("bei2: %.1f\n", bei2);
                double remain = t - once * bei2;
                //printf("remain: %.1f\n", remain);
                ans += bei2 * xunhuan;
                //printf("ans: %.1f\n",ans);
                if (remain <= k)
                {
                        ans += remain;
                }
                else
                {
                        ans += k + (remain - k) * 2.0;
                }
                printf("%.1f\n", ans);
        }
}

D

anser[i][j][0]表示偶数步能到达 [1]表示奇数部能到达

每个点最多访问两次

#include <bits/stdc++.h>
#define PI acos(-1.0)
#define mem(a,b) memset((a),b,sizeof(a))
#define TS printf("!!!\n")
#define pb push_back
#define inf 1e9
//std::ios::sync_with_stdio(false);
using namespace std;
//priority_queue<int,vector<int>,greater<int>> que; get min
const double eps = 1.0e-10;
const double EPS = 1.0e-4;
typedef pair<int, int> pairint;
typedef long long ll;
typedef unsigned long long ull;
//const int maxn = 3e5 + 10;
const int  maxm = ;
const int turn[][] = {{, }, { -, }, {, }, {, -}};
//priority_queue<int, vector<int>, less<int>> que;
//next_permutation
ll mod = 3e7;
const int maxn = ;
int anser[][];
int visit[];
int flag = ;
int road[];
vector<int> pla[];
void dfs(int now, int x)
{
        visit[now] = ;
        anser[now][x % ] = ;
        road[x] = now;
        int to;
        int len = pla[now].size();
        if (len ==  && (x %  == ))
        {
                cout << "Win" << endl;
                for (int i = ; i <= x; i++)
                {
                        cout << road[i] << " ";
                }
                exit();
        }
        else
        {
                for (int i = ; i < len; i++)
                {
                        to = pla[now][i];
                        if (visit[to] == )
                        {
                                flag = ;
                                if (anser[to][(x + ) % ] == )
                                {
                                        continue;
                                }
                                dfs(to, x + );
                        }
                        else
                        {
                                if (anser[to][(x + ) % ] == )
                                {
                                        continue;
                                }
                                dfs(to, x + );
                        }
                }
        }
        visit[now] = ;
}
int main()
{
        for (int i = ; i <= ; i++)
        {
                for (int j = ; j <= ; j++)
                {
                        anser[i][j] = -;
                }
        }
        int n, m;
        int num;
        int to;
        cin >> n >> m;
        for (int i = ; i <= n; i++)
        {
                scanf("%d", &num);
                for (int j = ; j <= num; j++)
                {
                        scanf("%d", &to);
                        pla[i].pb(to);
                }
        }
        int aim;
        cin >> aim;
        dfs(aim, );
        if (flag)
        {
                cout << "Draw" << endl;
                return ;
        }
        cout << "Lose" << endl;
}