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답안 #585697

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
585697 2022-06-29T08:31:26 Z 조영욱(#8387) Star Trek (CEOI20_startrek) C++17
43 / 100
 1000 ms 13220 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*i-1)*(d1+d3)+s*(d4-d3);
        s%=mod;
        s+=mod;
        s%=mod;
    }
    long long ret=fastpow(n,2*d-1)*one+four*s+three*(fastpow(n,2*d-1)-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

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 3412 KB Output is correct
2 Correct 67 ms 3448 KB Output is correct

Subtask #2
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 3432 KB Output is correct
2 Correct 4 ms 3424 KB Output is correct
3 Execution timed out 1076 ms 3420 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 5 ms 3412 KB Output is correct
3 Correct 6 ms 3444 KB Output is correct
4 Correct 4 ms 3444 KB Output is correct
5 Correct 6 ms 3412 KB Output is correct
6 Correct 4 ms 3412 KB Output is correct

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 5 ms 3412 KB Output is correct
3 Correct 6 ms 3444 KB Output is correct
4 Correct 4 ms 3444 KB Output is correct
5 Correct 6 ms 3412 KB Output is correct
6 Correct 4 ms 3412 KB Output is correct
7 Correct 70 ms 3412 KB Output is correct
8 Correct 73 ms 3540 KB Output is correct
9 Correct 50 ms 3452 KB Output is correct
10 Correct 60 ms 3452 KB Output is correct
11 Correct 58 ms 3412 KB Output is correct

Subtask #5
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 5 ms 3412 KB Output is correct
3 Correct 6 ms 3444 KB Output is correct
4 Correct 4 ms 3444 KB Output is correct
5 Correct 6 ms 3412 KB Output is correct
6 Correct 4 ms 3412 KB Output is correct
7 Correct 70 ms 3412 KB Output is correct
8 Correct 73 ms 3540 KB Output is correct
9 Correct 50 ms 3452 KB Output is correct
10 Correct 60 ms 3452 KB Output is correct
11 Correct 58 ms 3412 KB Output is correct
12 Execution timed out 1092 ms 13220 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #6
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 5 ms 3412 KB Output is correct
3 Correct 6 ms 3444 KB Output is correct
4 Correct 4 ms 3444 KB Output is correct
5 Correct 6 ms 3412 KB Output is correct
6 Correct 4 ms 3412 KB Output is correct
7 Correct 70 ms 3412 KB Output is correct
8 Correct 73 ms 3540 KB Output is correct
9 Correct 50 ms 3452 KB Output is correct
10 Correct 60 ms 3452 KB Output is correct
11 Correct 58 ms 3412 KB Output is correct
12 Correct 2 ms 3412 KB Output is correct
13 Correct 70 ms 3452 KB Output is correct
14 Correct 2 ms 3412 KB Output is correct
15 Correct 4 ms 3424 KB Output is correct
16 Correct 4 ms 3412 KB Output is correct
17 Correct 4 ms 3420 KB Output is correct
18 Correct 4 ms 3412 KB Output is correct
19 Correct 7 ms 3420 KB Output is correct
20 Correct 5 ms 3412 KB Output is correct
21 Correct 71 ms 3500 KB Output is correct
22 Correct 71 ms 3540 KB Output is correct
23 Correct 60 ms 3472 KB Output is correct
24 Correct 86 ms 3460 KB Output is correct
25 Correct 68 ms 3456 KB Output is correct
26 Correct 83 ms 3412 KB Output is correct
27 Correct 114 ms 3532 KB Output is correct
28 Correct 56 ms 3412 KB Output is correct
29 Correct 73 ms 3456 KB Output is correct
30 Correct 84 ms 3460 KB Output is correct

Subtask #7
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 3412 KB Output is correct
2 Correct 5 ms 3412 KB Output is correct
3 Correct 6 ms 3444 KB Output is correct
4 Correct 4 ms 3444 KB Output is correct
5 Correct 6 ms 3412 KB Output is correct
6 Correct 4 ms 3412 KB Output is correct
7 Correct 70 ms 3412 KB Output is correct
8 Correct 73 ms 3540 KB Output is correct
9 Correct 50 ms 3452 KB Output is correct
10 Correct 60 ms 3452 KB Output is correct
11 Correct 58 ms 3412 KB Output is correct
12 Execution timed out 1092 ms 13220 KB Time limit exceeded
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 3412 KB Output is correct
2 Correct 67 ms 3448 KB Output is correct
3 Correct 2 ms 3432 KB Output is correct
4 Correct 4 ms 3424 KB Output is correct
5 Execution timed out 1076 ms 3420 KB Time limit exceeded
6 Halted 0 ms 0 KB -