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답안 #585602

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
585602 2022-06-29T06:08:55 Z 박상훈(#8384) Star Trek (CEOI20_startrek) C++17
45 / 100
 107 ms 14136 KB 
#include <bits/stdc++.h>

typedef long long ll;
using namespace std;
const int MOD = 1e9+7;
vector<int> adj[100100];
bool _win[100100], _win_pa[100100], _win_root[100100], ok[100100];

void dfs1(int s, int pa = -1){
    int wcnt = 0, lcnt = 0;
    for (auto &v:adj[s]) if (v!=pa){
        dfs1(v, s);
        if (_win[v]) wcnt++;
        else lcnt++;
    }

    if (!lcnt) _win[s] = 0;
    else _win[s] = 1;

    if (lcnt<=1) ok[s] = 1;
}

void dfs2(int s, int pa = -1){
    int wcnt = 0, lcnt = 0;
    for (auto &v:adj[s]) if (v!=pa){
        if (_win[v]) wcnt++;
        else lcnt++;
    }
    if (pa!=-1){
        if (_win_pa[s]) wcnt++;
        else lcnt++;
    }

    for (auto &v:adj[s]) if (v!=pa){
        if (_win[v]) wcnt--;
        else lcnt--;

        if (!lcnt) _win_pa[v] = 0;
        else _win_pa[v] = 1;

        if (_win[v]) wcnt++;
        else lcnt++;
    }

    if (!lcnt) _win_root[s] = 0;
    else _win_root[s] = 1;

    for (auto &v:adj[s]) if (v!=pa) dfs2(v, s);
}

int lscnt = 0;
void dfs3(int s, int pa = -1){
    if (!ok[s]) return;
    if (!_win[s]) lscnt++;
    for (auto &v:adj[s]) if (v!=pa){
        if (!_win[s]) dfs3(v, s);
        else if (!_win[v]) dfs3(v, s);
    }
}

ll pw(ll a, ll e){
    if (!e) return 1;
    ll ret = pw(a, e/2);
    if (e&1) return ret*ret%MOD*a%MOD;
    return ret*ret%MOD;
}

int main(){
    int n;
    ll d;
    scanf("%d %lld", &n, &d);
    if (n==2) {printf("%lld\n", pw(4, d)); return 0;}

    for (int i=1;i<=n-1;i++){
        int x, y;
        scanf("%d %d", &x, &y);
        adj[x].push_back(y);
        adj[y].push_back(x);
    }

    dfs1(1);
    dfs2(1);
    dfs3(1);

    /*
    for (int i=1;i<=n;i++) printf("%d ", _win[i]); printf("\n");
    for (int i=1;i<=n;i++) printf("%d ", _win_pa[i]); printf("\n");
    for (int i=1;i<=n;i++) printf("%d ", _win_root[i]); printf("\n");
    for (int i=1;i<=n;i++) printf("%d ", ok[i]); printf("\n");
    */

    int lcnt = 0;
    for (int i=1;i<=n;i++) if (!_win_root[i]) lcnt++;

    ll ans = 0;
    if (_win[1]) ans = (ll)n*n - (ll)lscnt * lcnt;
    else ans = (ll)lscnt * lcnt;
    ans %= MOD;

    printf("%lld\n", ans);
    return 0;
}

Compilation message

startrek.cpp: In function 'int main()':
startrek.cpp:71:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |     scanf("%d %lld", &n, &d);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~
startrek.cpp:76:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Incorrect 2 ms 2664 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 2 ms 2664 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct

Subtask #3
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2660 KB Output is correct
4 Correct 1 ms 2656 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2656 KB Output is correct

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2660 KB Output is correct
4 Correct 1 ms 2656 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2656 KB Output is correct
7 Correct 2 ms 2660 KB Output is correct
8 Correct 2 ms 2664 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct

Subtask #5
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2660 KB Output is correct
4 Correct 1 ms 2656 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2656 KB Output is correct
7 Correct 2 ms 2660 KB Output is correct
8 Correct 2 ms 2664 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 67 ms 9832 KB Output is correct
13 Correct 107 ms 14136 KB Output is correct
14 Correct 47 ms 6716 KB Output is correct
15 Correct 54 ms 6444 KB Output is correct
16 Correct 76 ms 6476 KB Output is correct

Subtask #6
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2660 KB Output is correct
4 Correct 1 ms 2656 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2656 KB Output is correct
7 Correct 2 ms 2660 KB Output is correct
8 Correct 2 ms 2664 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 2 ms 2644 KB Output is correct
13 Incorrect 3 ms 2644 KB Output isn't correct
14 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct
3 Correct 2 ms 2660 KB Output is correct
4 Correct 1 ms 2656 KB Output is correct
5 Correct 1 ms 2644 KB Output is correct
6 Correct 2 ms 2656 KB Output is correct
7 Correct 2 ms 2660 KB Output is correct
8 Correct 2 ms 2664 KB Output is correct
9 Correct 2 ms 2644 KB Output is correct
10 Correct 2 ms 2644 KB Output is correct
11 Correct 2 ms 2644 KB Output is correct
12 Correct 67 ms 9832 KB Output is correct
13 Correct 107 ms 14136 KB Output is correct
14 Correct 47 ms 6716 KB Output is correct
15 Correct 54 ms 6444 KB Output is correct
16 Correct 76 ms 6476 KB Output is correct
17 Correct 2 ms 2644 KB Output is correct
18 Incorrect 3 ms 2644 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Incorrect 2 ms 2664 KB Output isn't correct
3 Halted 0 ms 0 KB -