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Submission #585694

# Submission time Handle Problem Language Result Execution time Memory
585694 2022-06-29T08:28:27 Z 조영욱(#8387) Star Trek (CEOI20_startrek) C++17
23 / 100
 1000 ms 13124 KB 
#include <bits/stdc++.h>
using namespace std;

int n;
long long d;
const int mod=1e9+7;

long long fastpow(long long a,long long b) {
    if (b==0) {
        return 1;
    }
    if (b%2==1) {
        return (fastpow(a,b-1)*a)%mod;
    }
    long long half=fastpow(a,b/2);
    return (half*half)%mod;
}

vector<int> adj[100001];
int dp[100001];
int dp1[100001];
int dep[100001];
int deg[1001];

void dfs1(int v,int prev) {
    for(int i=0;i<adj[v].size();i++) {
        int nt=adj[v][i];
        if (nt==prev){
            continue;
        }
        dep[nt]=dep[v]+1;
        dfs1(nt,v);
        deg[v]++;
        if (dp[nt]==0) {
            dp[v]++;
        }
    }
}

void dfs2(int v,int prev) {
    if (prev==0) {
        dp1[v]=1;
    }
    for(int i=0;i<adj[v].size();i++) {
        int nt=adj[v][i];
        if (nt==prev) {
            continue;
        }
        if (dp[nt]==0&&dp[v]>1) {
            dp1[nt]=0;
        }
        else if (dp[nt]>0&&dp[v]>0) {
            dp1[nt]=0;
        }
        else {
            dp1[nt]=2-dp1[v];
        }
        dfs2(nt,v);
    }
}

void dfs3(int v,int prev) {
    if (prev==0) {
        dp1[v]=0;
    }
    for(int i=0;i<adj[v].size();i++) {
        int nt=adj[v][i];
        if (nt==prev) {
            continue;
        }
        if (dp[nt]==0&&dp[v]>1) {
            dp1[nt]=0;
        }
        else if (dp[nt]>0&&dp[v]>0) {
            dp1[nt]=0;
        }
        else {
            dp1[nt]=1-dp1[v];
        }
        dfs3(nt,v);
    }
}

    long long d1,d2,d3,d4;
    long long one,two,three,four;

int main(void) {
    scanf("%d %lld",&n,&d);
    for(int i=1;i<n;i++) {
        int u,v;
        scanf("%d %d",&u,&v);
adj[u].push_back(v);
adj[v].push_back(u);
    }
    long long s=0;
dfs1(1,0);
dfs3(1,0);
for(int i=1;i<=n;i++)  if (dp[i]!=0||dp1[i]!=0) { s++;}
//printf("%lld\n",s);
    for(int i=1;i<=n;i++) {
        memset(dp,0,sizeof(dp));
        memset(dp1,0,sizeof(dp1));
        memset(deg,0,sizeof(deg));
        dep[i]=0;
        dfs1(i,0);
        dfs2(i,0);
        for(int j=1;j<=n;j++) {
            if (dp[j]>0) {
                d1++;
if (j==1) one++;
            }
            else if (i==j) {
                d3++;
if (j==1) three++;
            }
            else if (dp1[j]==2) {
                d1++;
if (j==1) one++;
            }
            else if (dp1[j]==0) {
                d2++;
if (j==1) two++;
            }
            else {
                if (dep[i]%2==dep[j]%2) {
                    d3++;
if (j==1) three++;
                }
                else {
                    d4++;
if (j==1) four++;
                }
            }
//printf("%d %d %d %d %d %d\n",i,j,one,two,three,four);
        }
    }
//printf("%lld %lld %lld %lld\n",one,two,three,four);
    for(int i=1;i<d;i++) {
        s=fastpow(n,2*d-1)*(d1+d3)+s*(d4-d3);
        s%=mod;
        s+=mod;
        s%=mod;
    }
    long long ret=n*one+four*s+three*(n-s);
    ret%=mod;
    ret+=mod;
    ret%=mod;
    printf("%lld",ret);
}

Compilation message

startrek.cpp: In function 'void dfs1(int, int)':
startrek.cpp:26:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 |     for(int i=0;i<adj[v].size();i++) {
      |                 ~^~~~~~~~~~~~~~
startrek.cpp: In function 'void dfs2(int, int)':
startrek.cpp:44:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   44 |     for(int i=0;i<adj[v].size();i++) {
      |                 ~^~~~~~~~~~~~~~
startrek.cpp: In function 'void dfs3(int, int)':
startrek.cpp:66:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   66 |     for(int i=0;i<adj[v].size();i++) {
      |                 ~^~~~~~~~~~~~~~
startrek.cpp: In function 'int main()':
startrek.cpp:88:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |     scanf("%d %lld",&n,&d);
      |     ~~~~~^~~~~~~~~~~~~~~~~
startrek.cpp:91:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |         scanf("%d %d",&u,&v);
      |         ~~~~~^~~~~~~~~~~~~~~

Subtask #1
0.0 / 0.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Incorrect 58 ms 3456 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 7.0

# Verdict Execution time Memory Grader output
1 Incorrect 2 ms 3412 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 4 ms 3412 KB Output is correct
3 Correct 4 ms 3412 KB Output is correct
4 Correct 6 ms 3412 KB Output is correct
5 Correct 4 ms 3412 KB Output is correct
6 Correct 6 ms 3412 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 4 ms 3412 KB Output is correct
3 Correct 4 ms 3412 KB Output is correct
4 Correct 6 ms 3412 KB Output is correct
5 Correct 4 ms 3412 KB Output is correct
6 Correct 6 ms 3412 KB Output is correct
7 Correct 70 ms 3412 KB Output is correct
8 Correct 71 ms 3540 KB Output is correct
9 Correct 50 ms 3456 KB Output is correct
10 Correct 65 ms 3412 KB Output is correct
11 Correct 61 ms 3412 KB Output is correct

Subtask #5
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 4 ms 3412 KB Output is correct
3 Correct 4 ms 3412 KB Output is correct
4 Correct 6 ms 3412 KB Output is correct
5 Correct 4 ms 3412 KB Output is correct
6 Correct 6 ms 3412 KB Output is correct
7 Correct 70 ms 3412 KB Output is correct
8 Correct 71 ms 3540 KB Output is correct
9 Correct 50 ms 3456 KB Output is correct
10 Correct 65 ms 3412 KB Output is correct
11 Correct 61 ms 3412 KB Output is correct
12 Execution timed out 1084 ms 13124 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 4 ms 3412 KB Output is correct
3 Correct 4 ms 3412 KB Output is correct
4 Correct 6 ms 3412 KB Output is correct
5 Correct 4 ms 3412 KB Output is correct
6 Correct 6 ms 3412 KB Output is correct
7 Correct 70 ms 3412 KB Output is correct
8 Correct 71 ms 3540 KB Output is correct
9 Correct 50 ms 3456 KB Output is correct
10 Correct 65 ms 3412 KB Output is correct
11 Correct 61 ms 3412 KB Output is correct
12 Correct 2 ms 3412 KB Output is correct
13 Incorrect 67 ms 3452 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 4 ms 3412 KB Output is correct
3 Correct 4 ms 3412 KB Output is correct
4 Correct 6 ms 3412 KB Output is correct
5 Correct 4 ms 3412 KB Output is correct
6 Correct 6 ms 3412 KB Output is correct
7 Correct 70 ms 3412 KB Output is correct
8 Correct 71 ms 3540 KB Output is correct
9 Correct 50 ms 3456 KB Output is correct
10 Correct 65 ms 3412 KB Output is correct
11 Correct 61 ms 3412 KB Output is correct
12 Execution timed out 1084 ms 13124 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Incorrect 58 ms 3456 KB Output isn't correct
3 Halted 0 ms 0 KB -