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답안 #659647

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
659647 2022-11-18T21:06:45 Z Lobo Star Trek (CEOI20_startrek) C++17
43 / 100
 1000 ms 62072 KB 
#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

const int maxn = 5e5+10;
const int mod = 1e9+7;

int n, d, dpw[maxn][2], dpl[maxn][2], dpwup[maxn][2], dplup[maxn][2];
vector<int> g[maxn];
int SL, SW, SL0, SW0, SWb, SLb;

void dfs1(int u, int ant) {
    dpw[u][1] = SW*dpw[u][0] + SL*(dpw[u][0]+dpl[u][0]); dpw[u][1]%= mod;
    dpl[u][1] = SW*dpl[u][0]; dpl[u][1]%= mod;

    int qtl = 0;
    for(auto v : g[u]) if(v != ant) {
        qtl+= dpl[v][0];
        dfs1(v,u);
    }

    for(auto v : g[u]) if(v != ant) {
        qtl-= dpl[v][0];
        if(qtl) {
            dpw[u][1]+= dpw[v][1]+dpl[v][1]; dpw[u][1]%= mod;
            dpl[u][1]+= 0;
        }
        else {
            dpw[u][1]+= dpl[v][1]; dpw[u][1]%= mod;
            dpl[u][1]+= dpw[v][1]; dpl[u][1]%= mod;
        }
        qtl+= dpl[v][0];
    }
}

int dw[maxn][2], dl[maxn][2], sdw[maxn][2], sdl[maxn][2], sbsz[maxn];
set<int> dl0s[maxn];

void calc(int u) {
    if(sdl[u][0] >= 1) {
        dw[u][0] = 1;
    }
    else {
        dw[u][0] = 0;
    }

    if(sdl[u][0] >= 2) {
        dw[u][1] = 1+sdw[u][1]+sdl[u][1];
    }
    else if(sdl[u][0] == 1) {
        dw[u][1] = 1+sdw[u][1]+sdl[u][1];
        int v1 = *dl0s[u].begin();
        dw[u][1]-= dw[v1][1];
    }
    else {
        dw[u][1] = 1+sdl[u][1];
    }
    dl[u][0] = 1-dw[u][0];
    dl[u][1] = sbsz[u]-dw[u][1];
}
void sol(int u, int ant) {
    dw[u][0] = 0;
    dl[u][0] = 0;
    sdw[u][0] = 0;
    sdl[u][0] = 0;
    dw[u][1] = 0;
    dl[u][1] = 0;
    sdw[u][1] = 0;
    sdl[u][1] = 0;
    sbsz[u] = 1;
    dl0s[u].clear();
    for(auto v : g[u]) if(v != ant) {
        sol(v,u);
        sdw[u][0]+= dw[v][0];
        sdw[u][1]+= dw[v][1];
        sdl[u][0]+= dl[v][0];
        sdl[u][1]+= dl[v][1];
        sbsz[u]+= sbsz[v];
        if(dl[v][0]) {
            dl0s[u].insert(v);
        }
    }

    calc(u);
}

void dfs0(int u, int ant) {
    dpw[u][0] = 0;
    int qtl = 0;
    for(auto v : g[u]) if(v != ant) {
        dfs0(v,u);
        qtl+= dpl[v][0];
    }

    if(qtl) dpw[u][0] = 1;
    dpl[u][0] = 1-dpw[u][0];
}

void dfs0up(int u, int ant) {
    int qtl = 0;
    for(auto v : g[u]) if(v != ant) {
        qtl+= dpl[v][0];
    }

    for(auto v : g[u]) if(v != ant) {
        qtl-= dpl[v][0];
        if(qtl || dpwup[u][0]) {
            dpwup[v][0] = 0;
            dplup[v][0] = 1-dpwup[v][0];
        }
        else {
            dpwup[v][0] = 1;
            dplup[v][0] = 1-dpwup[v][0];
        }
        qtl+= dpl[v][0];
    }

    for(auto v : g[u]) if(v != ant) {
        dfs0up(v,u);
    }
}

void solve() {
    cin >> n >> d;

    for(int i = 1; i <= n-1; i++) {
        int u,v; cin >> u >> v;
        g[u].pb(v);
        g[v].pb(u);
    }

    dfs0(1,0);
    dpwup[1][0] = 0;
    dplup[1][0] = 1;
    dfs0up(1,0);
    for(int i = 1; i <= n; i++) {
        if(dpw[i][0] || dpwup[i][0]) SW0++;
        else SL0++;
    }

    for(int i = 1; i <= n; i++) {
        sol(i,0);
        SWb+= dw[i][1];
        // cout << i << " " << dw[i][1] << endl;
    }
    SLb = n*n-SWb;

    // cout << SWb << " " << SLb << endl;
    // cout << SW0 << " " << SL0 << endl;
    SWb%= mod;
    SLb%= mod;
    SW = SW0;
    SL = SL0;
    for(int i = 1; i <= d-1; i++) {
        int newSW = n*(SW*SW0%mod)%mod + SL*SWb; newSW%= mod;
        int newSL = n*(SW*SL0%mod)%mod + SL*SLb; newSL%= mod;
        SW = newSW;
        SL = newSL;
    }
    dfs1(1,0);
    // cout << SW << " " << SL << endl;
    cout << dpw[1][1] << endl;
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 35540 KB Output is correct
2 Correct 68 ms 35792 KB Output is correct

Subtask #2
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 20 ms 35584 KB Output is correct
2 Correct 18 ms 35488 KB Output is correct
3 Execution timed out 1080 ms 35580 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 16 ms 35540 KB Output is correct
2 Correct 19 ms 35564 KB Output is correct
3 Correct 17 ms 35528 KB Output is correct
4 Correct 17 ms 35580 KB Output is correct
5 Correct 18 ms 35632 KB Output is correct
6 Correct 19 ms 35556 KB Output is correct

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 16 ms 35540 KB Output is correct
2 Correct 19 ms 35564 KB Output is correct
3 Correct 17 ms 35528 KB Output is correct
4 Correct 17 ms 35580 KB Output is correct
5 Correct 18 ms 35632 KB Output is correct
6 Correct 19 ms 35556 KB Output is correct
7 Correct 83 ms 35844 KB Output is correct
8 Correct 65 ms 35868 KB Output is correct
9 Correct 51 ms 35796 KB Output is correct
10 Correct 65 ms 35788 KB Output is correct
11 Correct 67 ms 35796 KB Output is correct

Subtask #5
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 16 ms 35540 KB Output is correct
2 Correct 19 ms 35564 KB Output is correct
3 Correct 17 ms 35528 KB Output is correct
4 Correct 17 ms 35580 KB Output is correct
5 Correct 18 ms 35632 KB Output is correct
6 Correct 19 ms 35556 KB Output is correct
7 Correct 83 ms 35844 KB Output is correct
8 Correct 65 ms 35868 KB Output is correct
9 Correct 51 ms 35796 KB Output is correct
10 Correct 65 ms 35788 KB Output is correct
11 Correct 67 ms 35796 KB Output is correct
12 Execution timed out 1087 ms 62072 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #6
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 16 ms 35540 KB Output is correct
2 Correct 19 ms 35564 KB Output is correct
3 Correct 17 ms 35528 KB Output is correct
4 Correct 17 ms 35580 KB Output is correct
5 Correct 18 ms 35632 KB Output is correct
6 Correct 19 ms 35556 KB Output is correct
7 Correct 83 ms 35844 KB Output is correct
8 Correct 65 ms 35868 KB Output is correct
9 Correct 51 ms 35796 KB Output is correct
10 Correct 65 ms 35788 KB Output is correct
11 Correct 67 ms 35796 KB Output is correct
12 Correct 18 ms 35544 KB Output is correct
13 Correct 67 ms 35796 KB Output is correct
14 Correct 17 ms 35552 KB Output is correct
15 Correct 20 ms 35540 KB Output is correct
16 Correct 21 ms 35632 KB Output is correct
17 Correct 19 ms 35604 KB Output is correct
18 Correct 21 ms 35540 KB Output is correct
19 Correct 17 ms 35540 KB Output is correct
20 Correct 18 ms 35540 KB Output is correct
21 Correct 68 ms 35796 KB Output is correct
22 Correct 68 ms 35884 KB Output is correct
23 Correct 50 ms 35748 KB Output is correct
24 Correct 71 ms 35788 KB Output is correct
25 Correct 67 ms 35784 KB Output is correct
26 Correct 69 ms 35764 KB Output is correct
27 Correct 69 ms 35796 KB Output is correct
28 Correct 40 ms 35760 KB Output is correct
29 Correct 67 ms 35684 KB Output is correct
30 Correct 65 ms 35796 KB Output is correct

Subtask #7
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 16 ms 35540 KB Output is correct
2 Correct 19 ms 35564 KB Output is correct
3 Correct 17 ms 35528 KB Output is correct
4 Correct 17 ms 35580 KB Output is correct
5 Correct 18 ms 35632 KB Output is correct
6 Correct 19 ms 35556 KB Output is correct
7 Correct 83 ms 35844 KB Output is correct
8 Correct 65 ms 35868 KB Output is correct
9 Correct 51 ms 35796 KB Output is correct
10 Correct 65 ms 35788 KB Output is correct
11 Correct 67 ms 35796 KB Output is correct
12 Execution timed out 1087 ms 62072 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 18 ms 35540 KB Output is correct
2 Correct 68 ms 35792 KB Output is correct
3 Correct 20 ms 35584 KB Output is correct
4 Correct 18 ms 35488 KB Output is correct
5 Execution timed out 1080 ms 35580 KB Time limit exceeded
6 Halted 0 ms 0 KB -