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답안 #600314

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
600314 2022-07-20T17:43:45 Z jasmin Star Trek (CEOI20_startrek) C++14
30 / 100
 1000 ms 13664 KB 
#include<bits/stdc++.h>
using namespace std;
#define int long long

const int mod=1e9+7;
struct matrix{
    int a=1;
    int b=0;
    int c=0;
    int d=1;
};
matrix zero={1, 0, 0, 1};
vector<int> mul(matrix a, vector<int> b){
    vector<int> ans(2, -1);
    ans[0]=(a.a*b[0])%mod +(a.b*b[1])%mod;
    ans[0]%=mod;
    ans[1]=(a.c*b[0])%mod +(a.d*b[1])%mod;
    ans[1]%=mod;
    return ans;
}
matrix multiply(matrix a, matrix b){
    matrix ans;
    ans.a=(a.a*b.a)%mod + (a.b*b.c)%mod;
    ans.a%=mod;
    ans.b=(a.a*b.b)%mod + (a.b*b.d)%mod;
    ans.b%=mod;
    ans.c=(a.c*b.a)%mod + (a.d*b.c)%mod;
    ans.c%=mod;
    ans.d=(a.c*b.b)%mod + (a.d+b.d)%mod;
    ans.d%=mod;
    return ans;
}
matrix power(matrix a, int e){
    if(e==0){
        return zero;
    }

    matrix res=power(a, e/2);
    res=multiply(res, res);
    if(e%2==1){
        res=multiply(res, a);
    }
    return res;
}

vector<int> cnt_red_children;
vector<int> redchild;
bool dfs_win(int v, int p, vector<vector<int> >& adi){
    for(auto u: adi[v]){
        if(u==p) continue;

        if(!dfs_win(u, v, adi)){
            redchild[v]=u;
            cnt_red_children[v]++;
        }
    }
    return cnt_red_children[v]>0;
}
/*vector<bool> win_up;
int lose=0; //=n-c
void dfs_win2(int v, int p, vector<vector<int> >& adi){
    if(p==-1){
        win_up[v]=false;
    }
    else if(cnt_red_children[v]){
        if(cnt_red_children[p]==0 && !win_up[p]){
            win_up[v]=true;
        }
        else{
            win_up[v]=false;
        }
    }
    else if([v]==0){
        if(win_down[p]==1 && !win_up[p]){
            win_up[v]=true;
        }
        else{
            win_up[v]=false;
        }
    }

    if(!win_up[v] && !win_down[v]){
        lose++;
    } 

    for(auto u: adi[v]){
        if(u!=p) dfs_win2(u, v, adi);
    }
}*/

int redforce=0;
void dfs_redforce(int v, int p, vector<vector<int> >& adi){

    if(cnt_red_children[v]==0){ //red
        redforce++;
        for(auto u: adi[v]){
            if(u!=p) dfs_redforce(u, v, adi);
        }
    }
    else if(cnt_red_children[v]==1){ //green with one red child
        dfs_redforce(redchild[v], v, adi);
    }
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    //freopen("input1.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);

    int n, d;
    cin >> n >> d;
    vector<vector<int> > adi(n);
    for(int i=0; i<n-1; i++){
        int a,b;
        cin >> a >> b;
        adi[a-1].push_back(b-1);
        adi[b-1].push_back(a-1);
    }

    int G=0; int R=0;
    int g1=0; int r1=0;
    int c=0;
    for(int i=n-1; i>=0; i--){
        redforce=0;
        //win_up.assign(n, 0);
        redchild.assign(n, -1);
        cnt_red_children.assign(n, 0);

        bool we_win=dfs_win(i, -1, adi);
        //dfs_win2(i, -1, adi);
        dfs_redforce(i, -1, adi);

        if(we_win){
            c++;
            g1=n;
            r1=n-redforce;
        }
        else{
            g1=0;
            r1=redforce;
        }
        G+=g1;
        R+=r1;
    }

    //cout << "redforce: " << redforce << "\n";
    //cout << g1 << " " << r1 << " " << c << "\n";

    matrix m1={g1, r1, 0, 0};
    matrix m2={G, R, n*n-G, n*n-R};
    //matrix m2={G, n*n-G, R, n*n-R};
    matrix p=power(m2, d-1);
    vector<int> ans=mul(m1, mul(p, {c, n-c}));
    cout << ans[0] << "\n";
}

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 12 ms 400 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
7.0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct

Subtask #3
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 18 ms 436 KB Output is correct
8 Correct 24 ms 340 KB Output is correct
9 Correct 12 ms 396 KB Output is correct
10 Correct 14 ms 340 KB Output is correct
11 Correct 17 ms 340 KB Output is correct

Subtask #5
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 18 ms 436 KB Output is correct
8 Correct 24 ms 340 KB Output is correct
9 Correct 12 ms 396 KB Output is correct
10 Correct 14 ms 340 KB Output is correct
11 Correct 17 ms 340 KB Output is correct
12 Execution timed out 1097 ms 13664 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 18 ms 436 KB Output is correct
8 Correct 24 ms 340 KB Output is correct
9 Correct 12 ms 396 KB Output is correct
10 Correct 14 ms 340 KB Output is correct
11 Correct 17 ms 340 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Incorrect 12 ms 392 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 1 ms 212 KB Output is correct
4 Correct 1 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 18 ms 436 KB Output is correct
8 Correct 24 ms 340 KB Output is correct
9 Correct 12 ms 396 KB Output is correct
10 Correct 14 ms 340 KB Output is correct
11 Correct 17 ms 340 KB Output is correct
12 Execution timed out 1097 ms 13664 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 12 ms 400 KB Output isn't correct
3 Halted 0 ms 0 KB -