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답안 #585659

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
585659 2022-06-29T07:52:05 Z 반딧불(#8385) Star Trek (CEOI20_startrek) C++17
0 / 100
 2 ms 2644 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[100002];
int depth[100002];
int DP[100002];
int DProot[100002];
ll ans;

void dfs(int x, int p=-1){
    for(auto y: link[x]){
        if(y==p) continue;
        depth[y] = depth[x] + 1;
        dfs(y, x);
        if(!DP[y]) DP[x] = 1;
    }
}

void dfs2(int x, int p=-1, bool winUp = 0){
    DProot[x] = (DP[x] || winUp);
    int cnt = 0;
    for(auto y: link[x]) if(y!=p) cnt += !DP[y];
    for(auto y: link[x]){
        if(y==p) continue;
        dfs2(y, x, !winUp && !(cnt-!DP[y]));
    }
}

int dfsFind(int x, int p=-1){
    if(depth[x] % 2 == 0){ /// my turn
        int cnt = 0;
        for(auto y: link[x]){
            if(y!=p && !DP[y]) cnt++;
        }
        if(cnt > 1) return 0;
        assert(cnt == 1);
        for(auto y: link[x]){
            if(y!=p && !DP[y]) return dfsFind(y, x);
        }
    }
    else{
        int ret = 1;
        for(auto y: link[x]){
            if(y==p) continue;
            ret += dfsFind(y, x);
        }
        return ret;
    }
}

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

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);
    }
    dfs(1);
    dfs2(1);
//    for(int i=1; i<=n; i++) printf("%d ", DProot[i]);

    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 tmp = n - W - dfsFind(1);
        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", ans%MOD);
}

Compilation message

startrek.cpp: In function 'int dfsFind(int, int)':
startrek.cpp:62:1: warning: control reaches end of non-void function [-Wreturn-type]
   62 | }
      | ^
startrek.cpp: In function 'int dfsFind2(int, int)':
startrek.cpp:84:1: warning: control reaches end of non-void function [-Wreturn-type]
   84 | }
      | ^
startrek.cpp: In function 'int main()':
startrek.cpp:87:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   87 |     scanf("%d %lld", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~
startrek.cpp:90:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
0.0 / 0.0

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

Subtask #2
0 / 7.0

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

Subtask #3
0 / 8.0

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

Subtask #4
0 / 15.0

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

Subtask #5
0 / 15.0

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

Subtask #6
0 / 20.0

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

Subtask #8
0 / 15.0

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