Submission #1003558

#	Time	Username	Problem	Language	Result	Execution time	Memory
1003558		vjudge1	Party (INOI20_party)	C++17	30 / 100	286 ms	1616 KiB

Main

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
#define oo 1e9

const int MAX = 205 + 8, MOD = 1e9 + 7, LOGMAX = 200;
int n;
int Hcnt[LOGMAX][LOGMAX];
int RHcnt[LOGMAX][LOGMAX];

int binpow(int a, int b){
    int res = 1;
    while(b){
        if(b & 1) res = res * a % MOD;
        b /= 2;
        a = a * a % MOD;
    }
    return res;
}
int inv(int a){
    return binpow(a, MOD - 2);
}

int ans[LOGMAX];

int vis[MAX];
int H[MAX];
void dfs(int node, int h){
    if(vis[node] || node > n || node < 1) return;
    vis[node] = 1;
    H[h]++;
    dfs(node * 2, h + 1);
    dfs(node * 2 + 1, h + 1);
    dfs(node / 2, h + 1);
}


void solve(){
    cin >> n;
    int LG = 1, T = 1;
    while(T <= n / 2) {LG++; T *= 2;}
    if((1ll << LG) - 1 == n){
        cout << ans[LG] << '\n';
        return;
    }
    int res = 0;
    for(int i = 1; i <= n; i++){
        for(int j = 0; j <= n; j++){
            vis[j] = 0;
            H[j] = 0;
        } 
        dfs(i, 0);
        int oth = n;
        for(int j = 0; j <= n; j++){
            if(!H[j]) break;
            oth -= H[j];
            res = (res + j * (binpow(2, H[j]) - 1) % MOD * binpow(2, oth) % MOD) % MOD;
        }
    }
    cout << res * inv(binpow(2, n) - 1) % MOD << '\n';
}

signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    for(int z = 1; z < 63; z++){
        n = (1ll << z) - 1;
        int res = 0;
        int LG = z - 1;
        for(int i = 0; (1ll << i) <= n; i++){
            for(int j = 0; j <= LG + i; j++){
                Hcnt[i][j] = 0;
                RHcnt[i][j] = 0;
            }
            for(int j = 0; j <= LG - i; j++){
                Hcnt[i][j] = (1ll << j);
                RHcnt[i][j] = (1ll << max(0ll, j - 1));
            }
            if(i != 0){
                for(int j = 0; j <= LG + i - 1; j++){
                    RHcnt[i][j + 1] += RHcnt[i - 1][j];
                    Hcnt[i][j + 1] += RHcnt[i - 1][j];
                }
            }
            int oth = n;
            for(int j = 0; j <= LG + i; j++){
                oth -= Hcnt[i][j];
                res = (res + j * (binpow(2, Hcnt[i][j]) - 1 + MOD) % MOD * binpow(2, oth + i) % MOD) % MOD;
            }
        }
        ans[z] = res * inv((binpow(2, n) - 1 + MOD) % MOD) % MOD;
    }
    int t; cin >> t;
    while(t--){
        solve();
    }
}

• Subtask 1: 7 / 7
• Subtask 2: 23 / 23
• Subtask 3: 0 / 33
• Subtask 4: 0 / 37