Submission #1196090

#	Time	Username	Problem	Language	Result	Execution time	Memory
1196090		Zbyszek99	Star Trek (CEOI20_startrek)	C++20	50 / 100	1096 ms	17296 KiB

startrek

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define ull unsigned long long
#define ff first
#define ss second
#define pii pair<int,int>
#define pll pair<long long, long long>
#define vi vector<int>
#define vl vector<long long>
#define pb push_back
#define rep(i, b) for(int i = 0; i < (b); ++i)
#define rep2(i,a,b) for(int i = a; i <= (b); ++i)
#define rep3(i,a,b,c) for(int i = a; i <= (b); i+=c)
#define count_bits(x) __builtin_popcountll((x))
#define all(x) (x).begin(),(x).end()
#define siz(x) (int)(x).size()
#define forall(it,x) for(auto& it:(x))
using namespace __gnu_pbds;
using namespace std;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
//mt19937 mt;void random_start(){mt.seed(chrono::time_point_cast<chrono::milliseconds>(chrono::high_resolution_clock::now()).time_since_epoch().count());}
//ll los(ll a, ll b) {return a + (mt() % (b-a+1));}
const int INF = 1e9+50;
const ll INF_L = 1e18+40;
const ll MOD = 1e9+7;

struct node
{
    ll dp[2][2];
    int sub_siz = 0;
    bool is_win = 0;
};

struct dp_
{
    ll dp[2][2];
    dp_()
    {
        rep(d1,2) rep(d2,2) dp[d1][d2] = 0;
    }
    dp_ operator+(const dp_& other)
    {
        dp_ res;
        res.dp[0][0] = other.dp[0][0] * dp[0][0] + other.dp[1][0] * dp[0][1];
        res.dp[0][1] = other.dp[0][1] * dp[0][0] + other.dp[1][1] * dp[0][1];
        res.dp[1][0] = other.dp[0][0] * dp[1][0] + other.dp[1][0] * dp[1][1];
        res.dp[1][1] = other.dp[0][1] * dp[1][0] + other.dp[1][1] * dp[1][1];
        rep(d1,2) rep(d2,2) res.dp[d1][d2] %= MOD;
        return res;
    }
};

vi graph[100001];
node dp_node[100001];

void dfs1(int v, int pop)
{
    dp_node[v].sub_siz = 1;
    dp_node[v].is_win = 0;
    rep(d1,2) rep(d2,2) dp_node[v].dp[d1][d2] = 0;
    int los_cnt = 0;
    int win_cnt = 0;
    forall(it,graph[v])
    {
        if(it != pop)
        {
            dfs1(it,v);
            if(!dp_node[it].is_win) los_cnt++;
            else win_cnt++;
            dp_node[v].sub_siz += dp_node[it].sub_siz;
        }
    }
    if(los_cnt > 0) dp_node[v].is_win = 1;
    if(los_cnt >= 2)
    {
        dp_node[v].dp[1][0] = dp_node[v].sub_siz;
        dp_node[v].dp[1][1] = dp_node[v].sub_siz;
        dp_node[v].dp[0][0] = 0;
        dp_node[v].dp[0][1] = 0;
    }
    else if(los_cnt == 1)
    {
        int los_vert;
        forall(it,graph[v])
        {
            if(it != pop && !dp_node[it].is_win) los_vert = it;
        }
        dp_node[v].dp[1][1] = dp_node[v].sub_siz - dp_node[los_vert].sub_siz + dp_node[los_vert].dp[0][1];
        dp_node[v].dp[1][0] = dp_node[v].sub_siz - dp_node[los_vert].sub_siz + dp_node[los_vert].dp[0][0];
        dp_node[v].dp[0][1] = dp_node[los_vert].dp[1][1];
        dp_node[v].dp[0][0] = dp_node[los_vert].dp[1][0];
    }
    else
    {
        dp_node[v].dp[1][0] = 1;
        dp_node[v].dp[0][1] = 1;
        forall(it,graph[v])
        {
            if(it != pop)
            {
                dp_node[v].dp[1][1] += dp_node[it].dp[0][1];
                dp_node[v].dp[1][0] += dp_node[it].dp[0][0];
                dp_node[v].dp[0][1] += dp_node[it].dp[1][1];
                dp_node[v].dp[0][0] += dp_node[it].dp[1][0];
            }
        }
    }
}

int main()
{
    ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    //random_start();
    int n;
    ll D;
    cin >> n >> D;
    rep(i,n-1)
    {
        int a,b;
        cin >> a >> b;
        graph[a].pb(b);
        graph[b].pb(a);
    }
    dfs1(1,1);
    dp_ beg_tree;
    dp_ mid_tree;
    dp_ end_tree;
    rep(d1,2) rep(d2,2)
    {
        beg_tree.dp[d1][d2] = dp_node[1].dp[d1][d2];
    }
    rep2(i,1,n)
    {
        dfs1(i,i);
        if(dp_node[i].is_win) end_tree.dp[1][1]++;
        else end_tree.dp[0][1]++;
        rep(d1,2) rep(d2,2)
        {
            mid_tree.dp[d1][d2] += dp_node[i].dp[d1][d2];
            mid_tree.dp[d1][d2] %= MOD;
        }
    }
    D--;
    rep2(bit,0,61)
    {
        if(D & (1LL << bit))
        {
            beg_tree = beg_tree + mid_tree;
        }
        mid_tree = mid_tree + mid_tree;
    }
    beg_tree = beg_tree + end_tree;
    cout << beg_tree.dp[1][1] << "\n";
}

• Subtask 1: 0 / 0
• Subtask 2: 7 / 7
• Subtask 3: 8 / 8
• Subtask 4: 15 / 15
• Subtask 5: 0 / 15
• Subtask 6: 20 / 20
• Subtask 7: 0 / 20
• Subtask 8: 0 / 15