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Submission #600799

# Submission time Handle Problem Language Result Execution time Memory
600799 2022-07-21T07:53:56 Z jasmin Star Trek (CEOI20_startrek) C++14
30 / 100
 1000 ms 16208 KB 
#include<bits/stdc++.h>
//#include<iostream>
//#include<vector>
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;
}
 
bool dfs_win(int v, int p, vector<vector<int> >& adi, vector<int>& cnt_red_children, vector<int>& redchild){
    for(auto u: adi[v]){
        if(u==p) continue;
 
        if(!dfs_win(u, v, adi, cnt_red_children, redchild)){
            redchild[v]=u;
            cnt_red_children[v]++;
        }
    }
    return cnt_red_children[v]>0;
}
 
int dfs_redforce(int v, int p, vector<vector<int> >& adi, vector<int>& cnt_red_children, vector<int>& redchild){
    int redforce=0;
 
    if(cnt_red_children[v]==0){ //red
        redforce++;
        for(auto u: adi[v]){
            if(u!=p) redforce+=dfs_redforce(u, v, adi, cnt_red_children, redchild);
        }
    }
    else if(cnt_red_children[v]==1){ //green with one red child
        redforce+=dfs_redforce(redchild[v], v, adi, cnt_red_children, redchild);
    }
    return redforce;
}
 
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--){
        vector<int> redchild(n, -1);
        vector<int> cnt_red_children(n, 0);
 
        bool we_win=dfs_win(i, -1, adi, cnt_red_children, redchild);
        int redforce=dfs_redforce(i, -1, adi, cnt_red_children, redchild);
 
        if(we_win){
            c++;
            g1=n;
            r1=n-redforce;
        }
        else{
            g1=0;
            r1=redforce;
        }
        G+=g1; G%=mod;
        R+=r1; R%=mod;
    }
 
    //cout << g1 << " " << r1 << " " << c << "\n";
    //cout << G << " " << R << "\n";
 
    matrix m1={g1, r1, 0, 0};
    matrix m2={G, R, (n*n)-G, (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

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 14 ms 408 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 1 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 1 ms 212 KB Output is correct

Subtask #3
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 1 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 20 ms 452 KB Output is correct
8 Correct 26 ms 452 KB Output is correct
9 Correct 13 ms 340 KB Output is correct
10 Correct 17 ms 340 KB Output is correct
11 Correct 21 ms 380 KB Output is correct

Subtask #5
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 20 ms 452 KB Output is correct
8 Correct 26 ms 452 KB Output is correct
9 Correct 13 ms 340 KB Output is correct
10 Correct 17 ms 340 KB Output is correct
11 Correct 21 ms 380 KB Output is correct
12 Execution timed out 1087 ms 16208 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 20 ms 452 KB Output is correct
8 Correct 26 ms 452 KB Output is correct
9 Correct 13 ms 340 KB Output is correct
10 Correct 17 ms 340 KB Output is correct
11 Correct 21 ms 380 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Incorrect 15 ms 408 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 20 ms 452 KB Output is correct
8 Correct 26 ms 452 KB Output is correct
9 Correct 13 ms 340 KB Output is correct
10 Correct 17 ms 340 KB Output is correct
11 Correct 21 ms 380 KB Output is correct
12 Execution timed out 1087 ms 16208 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Incorrect 14 ms 408 KB Output isn't correct
3 Halted 0 ms 0 KB -