QOJ.ac

QOJ

ID	题目	提交者	结果	用时	内存	语言	文件大小	提交时间	测评时间
#624051	#5307. Subgraph Isomorphism	0x3fffffff	WA	56ms	3688kb	C++20	2.5kb	2024-10-09 14:49:46	2024-10-09 14:49:48

Judging History

你现在查看的是最新测评结果

[2024-10-09 14:49:48]
评测

测评结果：WA
用时：56ms
内存：3688kb

查看

[2024-10-09 14:49:46]
提交

answer

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 10;

using ULL = unsigned long long;
const ULL mask = mt19937_64(chrono::steady_clock::now().time_since_epoch().count())();

ULL shift(ULL x) {
    x ^= mask;
    x ^= x << 13;
    x ^= x >> 7;
    x ^= x << 17;
    x ^= mask;
    return x;
}

void solve() {
    int n, m; cin >> n >> m;
    vector<vector<int>>e(n + 1);
    vector<int>in(n + 1);
    for (int i = 1; i <= m; i++) {
        int a, b; cin >> a >> b;
        e[a].push_back(b);
        e[b].push_back(a);
        in[a]++; in[b]++;
    }
    if (m == n - 1) {
        cout << "YES\n"; return;
    }
    if (m > n) {
        cout << "NO\n"; return;
    }

    queue<int>q;
    vector<int>vis(n + 1, 1);
    for (int i = 1; i <= n; i++) {
        if (in[i] == 1) {
            q.push(i);
        }
    }
    int cnt = n;
    while (not q.empty()) {
        int u = q.front();
        q.pop();
        vis[u] = 0; cnt--;
        for (int v : e[u]) {
            if (vis[v] and --in[v] == 1) {
                q.push(v);
            }
        }
    }
    vector<ULL>h(n + 1);
    auto get = [&](auto && get, int u, int fa)->void{
        h[u] = 1;
        for (int v : e[u]) {
            if (v == fa || vis[v])continue;
            get(get, v, u);
            h[u] += shift(h[v]);
        }
    };

    for (int i = 1; i <= n; i++) {
        if (vis[i]) {
            get(get, i, 0);
        }
    }

    int su = 0, sv = 0;
    for (int i = 1; i <= n; i++) {
        if (vis[i]) {
            for (int v : e[i]) {
                if (vis[v]) {
                    su = i, sv = v;
                    break;
                }
            }
        }
        if (su)break;
    }

    vector<ULL>res;


    auto dfs = [&](auto && ff, int u, int fa)->void{
        res.push_back(h[u]);
        for (int v : e[u]) {
            if (v == fa || v == su)continue;
            ff(ff, v, u);
        }
    };
    dfs(dfs, su, sv);
    if (cnt & 1) {
        for (int i = 1; i < cnt; i++) {
            if (res[i - 1] != res[i]) {
                cout << "NO\n"; return;
            }
        }
    } else {
        for (int i = 2; i < cnt; i++) {
            if (res[i - 2] != res[i]) {
                cout << "NO\n"; return;
            }
        }
    }
    cout << "YES\n";
}

signed main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int tt = 1;
    cin >> tt;
    while (tt--)
        solve();
    return 0;
}

源文件, 语言: C++20

詳細信息

Test #1:

score: 100

Accepted

time: 0ms

memory: 3568kb

input:

output:

YES
YES
NO
YES

result:

ok 4 token(s): yes count is 3, no count is 1

Test #2:

score: -100

Wrong Answer

time: 56ms

memory: 3688kb

input:

output:

YES
YES
YES
YES
YES
NO
YES
NO
NO
YES
YES
NO
NO
NO
NO
NO
NO
YES
NO
NO
NO
NO
YES
NO
NO
NO
NO
NO
NO
NO
YES
YES
NO
YES
YES
NO
NO
NO
YES
NO
NO
NO
NO
NO
YES
NO
NO
NO
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO...

result:

wrong answer expected YES, found NO [60th token]