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답안 #585734

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
585734 2022-06-29T09:25:27 Z 반딧불(#8385) Star Trek (CEOI20_startrek) C++17
43 / 100
 1000 ms 8328 KB 
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
const ll MOD = 1000000007;

ll mpow(ll x, ll y){
    if(!y) return 1;
    if(y%2) return mpow(x, y-1) * x % MOD;
    ll tmp = mpow(x, y/2);
    return tmp*tmp%MOD;
}

int n;
ll k;
vector<int> link[1002];
ll mat[1002][1002];
ll depth[1002];
ll group[1002], groupCnt[2];
ll ans;

ll DP[2][1002];
ll find1[1002], find2[1002];

void dfs(int x, int p, int r){
    if(r==1){
        group[x] = depth[x]%2;
        groupCnt[group[x]]++;
    }
    for(auto y: link[x]){
        if(y==p) continue;
        depth[y] = depth[x] + 1;
        dfs(y, x, r);
        if(!mat[r][y]) mat[r][x] = 1;
    }
}

int dfsFind(int x, int p, int dp, int r){ /// ������ ������ �ϴ� ��� ���� �� ���� ã��
    if(dp % 2 == 0){ /// my turn
        int cnt = 0;
        for(auto y: link[x]){
            if(y!=p && !mat[r][y]) cnt++;
        }
        if(cnt > 1) return 0;
        assert(cnt == 1);
        for(auto y: link[x]){
            if(y!=p && !mat[r][y]) return dfsFind(y, x, dp+1, r);
        }
        exit(1);
    }
    else{ /// your turn
        int ret = 1;
        for(auto y: link[x]){
            if(y==p) continue;
            ret += dfsFind(y, x, dp+1, r);
        }
        return ret;
    }
}

int dfsFind2(int x, int p, int dp, int r){
    if(dp % 2 == 0){ /// my turn
        int ret = 1;
        for(auto y: link[x]){
            if(y==p) continue;
            ret += dfsFind2(y, x, dp+1, r);
        }
        return ret;
    }
    else{ /// your turn
        int cnt = 0;
        for(auto y: link[x]){
            if(y!=p && !mat[r][y]) cnt++;
        }
        if(cnt > 1) return 0;
        assert(cnt == 1);
        for(auto y: link[x]){
            if(y!=p && !mat[r][y]) return dfsFind2(y, x, dp+1, r);
        }
        exit(1);
    }
}

int main(){
    scanf("%d %lld", &n, &k);
    for(int i=1; i<n; i++){
        int x, y;
        scanf("%d %d", &x, &y);
        link[x].push_back(y);
        link[y].push_back(x);
    }
//    for(int i=n; i>=1; i--){
//        for(int x=0; x<=n+1; x++) depth[x] = DP[x] = 0;
//        dfs(i), DProot[i] = DP[i];
//    }
//    for(int i=1; i<=n; i++) printf("%d ", DProot[i]);

    for(int i=1; i<=n; i++){
        dfs(i, -1, i);
        if(mat[i][i]) find1[i] = groupCnt[!group[i]] - dfsFind(i, -1, 0, i);
        else find2[i] = dfsFind2(i, -1, 0, i);
        DP[0][i] = mat[i][i];
    }

    for(int turn=1; turn<=k; turn++){
        int b = turn%2;

        /// ��ó��
        ll Wsum = 0; /// �̱�� ������
        for(int i=1; i<=n; i++) Wsum = (Wsum + DP[!b][i]) % MOD;
        ll Lsum = (mpow(n, 2*turn-1) - Wsum + MOD) % MOD; /// ���� ������

        /// ���� ���
        for(int i=1; i<=n; i++){
            DP[b][i] = 0;
            if(mat[i][i]){ /// ���⼭ �����ϸ� �̱�� ���
                /// ? -> W
                DP[b][i] = (DP[b][i] + Wsum * n) % MOD;
                /// my turn -> L
                DP[b][i] = (DP[b][i] + groupCnt[group[i]] * Lsum) % MOD;
                /// your turn -> L
                DP[b][i] = (DP[b][i] + find1[i] * Lsum) % MOD;
            }
            else{
                DP[b][i] = (DP[b][i] + find2[i] * Lsum) % MOD;
            }
        }
    }

//    if(DP[1]){ /// ���������� �̱� ��
//        ll W = 0; /// ? -> W
//        for(int i=1; i<=n; i++) if(DProot[i]) W++;
//        ans += W*n;
//
//        ll myturn = 0; /// my turn -> L
//        for(int i=1; i<=n; i++) if(depth[i] % 2 == 0) myturn++;
//        ans += myturn * (n-W);
//
//        ll dw = 0;
//        for(int i=1; i<=n; i++) if(DP[i]) dw++;
//        ll tmp = n - myturn - dfsFind(1); /// your turn -> L
//        ans += tmp * (n-W);
//    }
//    else{ /// ���������� �� ��
//        ll L = 0;
//        for(int i=1; i<=n; i++) if(!DProot[i]) L++;
//        ans += L * dfsFind2(1);
//    }

    printf("%lld", DP[k%2][1]);
}

Compilation message

startrek.cpp: In function 'int main()':
startrek.cpp:86:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   86 |     scanf("%d %lld", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~
startrek.cpp:89:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0.0 / 0.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 25 ms 8172 KB Output is correct

Subtask #2
0 / 7.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 3 ms 340 KB Output is correct
3 Execution timed out 1082 ms 340 KB Time limit exceeded
4 Halted 0 ms 0 KB -

Subtask #3
8.0 / 8.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 852 KB Output is correct
3 Correct 1 ms 724 KB Output is correct
4 Correct 1 ms 724 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 852 KB Output is correct

Subtask #4
15.0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 852 KB Output is correct
3 Correct 1 ms 724 KB Output is correct
4 Correct 1 ms 724 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 852 KB Output is correct
7 Correct 23 ms 8184 KB Output is correct
8 Correct 30 ms 8276 KB Output is correct
9 Correct 19 ms 8268 KB Output is correct
10 Correct 18 ms 8148 KB Output is correct
11 Correct 24 ms 8236 KB Output is correct

Subtask #5
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 852 KB Output is correct
3 Correct 1 ms 724 KB Output is correct
4 Correct 1 ms 724 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 852 KB Output is correct
7 Correct 23 ms 8184 KB Output is correct
8 Correct 30 ms 8276 KB Output is correct
9 Correct 19 ms 8268 KB Output is correct
10 Correct 18 ms 8148 KB Output is correct
11 Correct 24 ms 8236 KB Output is correct
12 Runtime error 1 ms 468 KB Execution killed with signal 11
13 Halted 0 ms 0 KB -

Subtask #6
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 852 KB Output is correct
3 Correct 1 ms 724 KB Output is correct
4 Correct 1 ms 724 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 852 KB Output is correct
7 Correct 23 ms 8184 KB Output is correct
8 Correct 30 ms 8276 KB Output is correct
9 Correct 19 ms 8268 KB Output is correct
10 Correct 18 ms 8148 KB Output is correct
11 Correct 24 ms 8236 KB Output is correct
12 Correct 0 ms 340 KB Output is correct
13 Correct 25 ms 8160 KB Output is correct
14 Correct 1 ms 340 KB Output is correct
15 Correct 3 ms 340 KB Output is correct
16 Correct 1 ms 724 KB Output is correct
17 Correct 1 ms 852 KB Output is correct
18 Correct 1 ms 724 KB Output is correct
19 Correct 1 ms 724 KB Output is correct
20 Correct 1 ms 852 KB Output is correct
21 Correct 23 ms 8252 KB Output is correct
22 Correct 30 ms 8284 KB Output is correct
23 Correct 18 ms 8136 KB Output is correct
24 Correct 21 ms 8168 KB Output is correct
25 Correct 25 ms 8208 KB Output is correct
26 Correct 634 ms 8284 KB Output is correct
27 Correct 762 ms 8328 KB Output is correct
28 Correct 589 ms 6668 KB Output is correct
29 Correct 667 ms 8232 KB Output is correct
30 Correct 427 ms 8284 KB Output is correct

Subtask #7
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 1 ms 852 KB Output is correct
3 Correct 1 ms 724 KB Output is correct
4 Correct 1 ms 724 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 852 KB Output is correct
7 Correct 23 ms 8184 KB Output is correct
8 Correct 30 ms 8276 KB Output is correct
9 Correct 19 ms 8268 KB Output is correct
10 Correct 18 ms 8148 KB Output is correct
11 Correct 24 ms 8236 KB Output is correct
12 Runtime error 1 ms 468 KB Execution killed with signal 11
13 Halted 0 ms 0 KB -

Subtask #8
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 25 ms 8172 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 3 ms 340 KB Output is correct
5 Execution timed out 1082 ms 340 KB Time limit exceeded
6 Halted 0 ms 0 KB -