oj.uz

Submission #703472

# Submission time Handle Problem Language Result Execution time Memory
703472 2023-02-27T13:13:19 Z Darren0724 Star Trek (CEOI20_startrek) C++17
30 / 100
 1000 ms 15212 KB 
#include <bits/stdc++.h>
using namespace std;
#define int long long
const int mod=1e9+7;
int n;
int cnt=0,idx=0,tmp=0;
int pw(int a,int b){
    int ans=1;
    while(b){
        if(b&1){
            ans=ans*a%mod;
        }
        b>>=1;
        a=a*a%mod;
    }
    return ans;
}
vector<vector<int>> adj;
vector<int> dp;
void dfs(int k,int pa){
    bool flag=0;
    for(int j:adj[k]){
        if(j==pa){
            continue;
        }
        dfs(j,k);
        if(dp[j]==0){
            flag=1;
        }
    }
    if(k==idx&&tmp==1){
        flag=1;
    }
    dp[k]=flag;
}
signed main(){
    cin>>n;
    int d;cin>>d;
    if(n==2){
        int p=pw(2,d*2);
        cout<<p<<endl;
        return 0;
    }
    adj.resize(n*2);
    for(int i=1;i<n;i++){
        int a,b;cin>>a>>b;a--;b--;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    for(int i=0;i<n;i++){
        dp.assign(n,-1);
        dfs(i,i);
        if(dp[i]==1){
            cnt++;
        }
    }
    int ans=0;
    for(int i=0;i<n;i++){
        idx=i;
        dp.assign(n,-1);
        tmp=0;
        dfs(0,0);
        if(dp[0]==1){
            ans+=cnt;
        }
        dp.assign(n,-1);
        tmp=1;
        dfs(0,0);
        if(dp[0]==1){
            ans+=n-cnt;
        }
    }
    cout<<ans%mod<<endl;

    return 0;
}

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 39 ms 376 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 0 ms 212 KB Output is correct
3 Correct 0 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

# Verdict Execution time Memory 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 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 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 46 ms 340 KB Output is correct
8 Correct 54 ms 340 KB Output is correct
9 Correct 34 ms 340 KB Output is correct
10 Correct 50 ms 340 KB Output is correct
11 Correct 46 ms 340 KB Output is correct

Subtask #5
0 / 15.0

# Verdict Execution time Memory 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 46 ms 340 KB Output is correct
8 Correct 54 ms 340 KB Output is correct
9 Correct 34 ms 340 KB Output is correct
10 Correct 50 ms 340 KB Output is correct
11 Correct 46 ms 340 KB Output is correct
12 Execution timed out 1076 ms 15212 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 46 ms 340 KB Output is correct
8 Correct 54 ms 340 KB Output is correct
9 Correct 34 ms 340 KB Output is correct
10 Correct 50 ms 340 KB Output is correct
11 Correct 46 ms 340 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Incorrect 40 ms 304 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory 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 1 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 46 ms 340 KB Output is correct
8 Correct 54 ms 340 KB Output is correct
9 Correct 34 ms 340 KB Output is correct
10 Correct 50 ms 340 KB Output is correct
11 Correct 46 ms 340 KB Output is correct
12 Execution timed out 1076 ms 15212 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Incorrect 39 ms 376 KB Output isn't correct
3 Halted 0 ms 0 KB -