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ID	Problem	Submitter	Result	Time	Memory	Language	File size	Submit time	Judge time
#75429	#5307. Subgraph Isomorphism	team1377^#	WA	50ms	6736kb	C++14	2.9kb	2023-02-05 10:25:50	2023-02-05 10:25:52

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[2023-10-15 17:24:15]
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测评结果：WA
用时：50ms
内存：6596kb

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[2023-08-10 23:21:45]
System Update: QOJ starts to keep a history of the judgings of all the submissions.

[2023-02-05 10:25:52]
评测

测评结果：0
用时：50ms
内存：6736kb

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[2023-02-05 10:25:50]
提交

answer

#include <bits/stdc++.h>

using namespace std;

const int N = 1e5 + 5;

vector<int> G[N];
vector<int> S, cyc;
int inS[N];

void dfs(int x, int fa = -1)
{
    S.push_back(x);
    inS[x] = 1;
    for (int i = 0; i < G[x].size(); ++i) {
        int v = G[x][i];
        if (v == fa) {
            continue;
        }
        if (inS[v]) {
            int p;
            do {
                p = S.back();
                S.pop_back();
                cyc.push_back(p);
            } while (p != v);
            return;
        }
        dfs(v, x);
        if (cyc.size()) {
            return;
        }
    }
    S.pop_back();
    inS[x] = 0;
    return;
}

int base[N], siz[N];

int hhash(int x, int fa = -1)
{
    siz[x] = 1;
    vector<int> tmp;
    for (int i = 0; i < G[x].size(); ++i) {
        int v = G[x][i];
        if (v == fa) {
            continue;
        }
        tmp.push_back(hhash(v, x));
        siz[x] += siz[v];
    }
    sort(tmp.begin(), tmp.end());
    int val = siz[x];
    for (int i = 0; i < tmp.size(); ++i) {
        val = (1ll * val * base[i] + tmp[i]) % 998244353;
    }
    return val;
}

signed main()
{
    mt19937 rnd;
    for (int i = 0; i < N; ++i) {
        base[i] = rnd() % 998244353;
    }
    int T;
    scanf("%d", &T);
    while (T--) {
        int n, m;
        scanf("%d%d", &n, &m);
        for (int i = 1; i <= n; ++i) {
            G[i].clear();
            inS[i] = 0;
        }
        for (int i = 1; i <= m; ++i) {
            int x, y;
            scanf("%d%d", &x, &y);
            G[x].push_back(y);
            G[y].push_back(x);
        }
        if (m == n - 1) {
            puts("YES");
        } else if (m != n) {
            puts("NO");
        } else {
            int flag = 1;
            for (int i = 1; i <= n; ++i) {
                if (G[i].size() != 2) {
                    flag = 0;
                    break;
                }
            }
            if (flag) {
                puts("YES");
                continue;
            }
            S.clear();
            cyc.clear();
            dfs(1);
            if (cyc.size() != 4) {
                puts("NO");
            } else {
                int a = cyc[0], b = cyc[1], c = cyc[2], d = cyc[3];
                if (G[a].size() != 3) {
                    int tmp = a;
                    a = b, b = c, c = d, d = tmp;
                }
                if (G[a].size() != 3 || G[b].size() != 2 || G[c].size() != 3 || G[d].size() != 2) {
                    puts("NO");
                } else {
                    int r1 = G[a][0] ^ G[a][1] ^ G[a][2] ^ b ^ d, r2 = G[c][0] ^ G[c][1] ^ G[c][2] ^ b ^ d;
                    if (hhash(r1, a) == hhash(r2, c)) {
                        puts("YES");
                    } else {
                        puts("NO");
                    }
                }
            }
        }
    }
    return 0;
}

Source code, Language: C++14

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100

Accepted

time: 4ms

memory: 6648kb

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: 50ms

memory: 6736kb

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
NO
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]