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QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#603394#8720. BFS 序 0llleiWA 225ms76008kbC++204.3kb2024-10-01 16:21:532024-10-01 16:21:53

Judging History

你现在查看的是最新测评结果

  • [2024-10-01 16:21:53]
  • 评测
  • 测评结果:WA
  • 用时:225ms
  • 内存:76008kb
  • [2024-10-01 16:21:53]
  • 提交

answer

#include <bits/stdc++.h>
using namespace std;
using LL = long long;

struct LCA {
    const int N;
    int n, idx;
    vector<int> id, rid, dep, fa;
    vector<vector<int>> e, st;

    LCA(int n) : N(__lg(n) + 1), n(n), idx(0), id(n, -1), rid(n), dep(n), fa(n), e(n), st(N, vector<int>(n)) {}

    void add(int u, int v) {
        e[u].push_back(v);
        e[v].push_back(u);
    }

    int getMin(int x, int y) {
        return dep[x] < dep[y] ? x : y;
    }

    void dfs(int u) {
        id[u] = idx;
        rid[idx] = u;
        idx++;

        for (int v : e[u]) {
            if (id[v] != -1) {
                continue;
            }

            dep[v] = dep[u] + 1;
            fa[v] = u;
            dfs(v);
        }
    }

    void work(int rt = 0) {
        dep[rt] = 1;
        dfs(rt);

        for (int i = 0; i < n; ++i) {
            st[0][i] = rid[i];
        }

        for (int i = 1; i < N; ++i) {
            for (int j = 0; j + (1 << i) - 1 < n; ++j) {
                st[i][j] = getMin(st[i - 1][j], st[i - 1][j + (1 << (i - 1))]);
            }
        }
    }

    int getLca(int x, int y) {
        if (x == y) {
            return x;
        }
        x = id[x], y = id[y];
        if (x > y) {
            swap(x, y);
        }
        ++x;
        int z = __lg(y - x + 1);
        return fa[getMin(st[z][x], st[z][y - (1 << z) + 1])];
    }
};


int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n;
    cin >> n;
    LCA lca(n);
    vector<vector<int>> e(n);
    for (int i = 1; i < n; ++i) {
        int f;
        cin >> f;
        --f;
        lca.add(f, i);
        e[f].push_back(i);
    }
    lca.work();

    vector<int> dep(n, -1);
    vector<int> dfn(n);
    int tot = 0;
    auto dfs = [&](auto &&self, int u) -> void {
        dfn[u] = tot++;
        for (int v : e[u]) {
            dep[v] = dep[u] + 1;
            self(self, v);
        }
    };

    dep[0] = 0;
    dfs(dfs, 0);

    int q;
    cin >> q;

    vector<vector<int>> ee(n);
    vector<int> d(n);

    auto solve = [&]() {
        int m;
        cin >> m;

        vector<int> a(m);
        vector<int> c(m);
        for (int i = 0; i < m; ++i) {
            cin >> a[i];
            --a[i];
            c[i] = a[i];
            if (i) {
                ee[a[i - 1]].push_back(a[i]);
                d[a[i]]++;
            }
        }

        for (int i = 1; i < m; ++i) {
            if (dep[a[i]] < dep[a[i - 1]]) {
                for (auto x : c) {
                    ee[x].clear();
                    d[x] = 0;
                }
                cout << "No\n";
                return;
            }
        }


        for (int i = 0; i < m; ++i) {
            int j = i;
            while (j < m && dep[a[j]] == dep[a[i]]) {
                ++j;
            }

            for (int k = i; k < j - 1; ++k) {
                int l = lca.getLca(a[k], a[k + 1]);

                int t1 = *prev(upper_bound(e[l].begin(), e[l].end(), a[k], [&](int x, int y) {
                    return dfn[x] < dfn[y];
                }));
                int t2 = *prev(upper_bound(e[l].begin(), e[l].end(), a[k + 1], [&](int x, int y) {
                    return dfn[x] < dfn[y];
                }));

                if (t1 != t2) {
                    ee[t1].push_back(t2);
                    d[t2]++;
                    c.push_back(t1);
                    c.push_back(t2);
                }
            }
            i = j;
        } 

        sort(c.begin(), c.end());
        c.erase(unique(c.begin(), c.end()), c.end());

        queue<int> q;
        for (auto x : c) {
            if (d[x] == 0) {
                q.push(x);
            }
        }
        int cnt = 0;

        while (q.size()) {
            int u = q.front();
            q.pop();
            ++cnt;
            for (int v : ee[u]) {
                --d[v];

                if (d[v] == 0) {
                    q.push(v);
                }
            }
        }

        for (auto x : c) {
            ee[x].clear();
            d[x] = 0;
        }

        if (cnt != c.size()) {
            cout << "No\n";
        } else {
            cout << "Yes\n";
        }
    };

    while (q--) {
        solve();
    }
    return 0;
}

Details

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Test #1:

score: 100
Accepted
time: 0ms
memory: 3824kb

input:

6
1 1 3 2 4
10
4 3 6 2 5
1 4
3 2 4 5
5 2 5 4 6 3
3 1 4 2
3 5 6 3
5 4 5 2 6 1
4 4 3 2 5
4 4 6 2 3
3 3 2 6

output:

No
Yes
Yes
No
No
No
No
No
No
Yes

result:

ok 10 token(s): yes count is 3, no count is 7

Test #2:

score: -100
Wrong Answer
time: 225ms
memory: 76008kb

input:

300000
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1...

output:

No
Yes
Yes
Yes
No
No
No
No
No
No
Yes
Yes
No
Yes
No
Yes
Yes
Yes
No
No
No
No
Yes
No
No
Yes
No
No
No
No
Yes
Yes
Yes
No
No
Yes
No
No
No
No
No
No
No
Yes
No
Yes
No
Yes
No
No
No
No
Yes
Yes
Yes
No
No
Yes
No
No
No
No
No
Yes
Yes
No
No
No
No
No
Yes
Yes
No
Yes
No
No
No
Yes
No
No
Yes
No
No
Yes
Yes
Yes
No
No
No
Y...

result:

wrong answer expected NO, found YES [181st token]