QOJ.ac

QOJ

IDProblemSubmitterResultTimeMemoryLanguageFile sizeSubmit timeJudge time
#415414#852. JellyfishMobed#AC ✓334ms20348kbC++142.3kb2024-05-20 21:06:342024-05-20 21:06:34

Judging History

你现在查看的是最新测评结果

  • [2024-05-20 21:06:34]
  • 评测
  • 测评结果:AC
  • 用时:334ms
  • 内存:20348kb
  • [2024-05-20 21:06:34]
  • 提交

answer

#include<bits/stdc++.h>

using namespace std;
const int inf = 1e9 + 1;
const int MOD = 1e9 + 7;

/*
const int N = 1e5 + 5;
int fac[N], inv[N];

int sum(int a, int b) { return (a + b + MOD + MOD) % MOD; }
int mul(int a, int b) { return 1ll * a * b % MOD; }
int Pow(int a, int b) {
    int res = 1;
    for (; b; b>>=1, a = mul(a, a)) if (b&1) {
        res = mul(res, a);
    }
    return res;
}
int C(int n, int k) {
    return mul(fac[n], mul(inv[k], inv[n - k]));
}
void prep() {
    fac[0] = 1;
    for (int i = 1; i < N; i++) fac[i] = mul(fac[i - 1], i);
    inv[N - 1] = Pow(fac[N - 1], MOD - 2);
    for (int i = N - 2; i >= 0; i--) inv[i] = mul(inv[i + 1], i + 1);
}
*/

const int N = 1e5 + 5;
vector<int> g[N];
vector<int> circle;
int mark[N];
int lf[N];

int dfs(int v, int p = 0) {
    mark[v] = 1;
    int ch = 0;
    for (int u : g[v]) if (u != p) {
        if (!mark[u]) {
            ch = max(ch, dfs(u, v));
        } else if (mark[u] == 1) {
            ch = 2;
            circle.push_back(u);
        }
    }
    if (!circle.empty() && v == circle[0]) 
        return 1;
    mark[v] = ch;
    if (mark[v] == 2) {
        circle.push_back(v);
    }
    return mark[v];
}

int count_leaf(int v, int r) {
    mark[v] = 2;
    int leaf = 0;
    for (int u : g[v]) if (mark[u] != 2) {
        leaf += count_leaf(u, r);
    }
    if (leaf == 0 && v != r)
        return 1;
    else
        return leaf;
}
void Solve() {
    int n; cin >> n;
    for (int i = 1; i <= n; i++) g[i].clear(), lf[i] = 0, mark[i] = 0;
    for (int i = 1; i <= n; i++) {
        int u, v; cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    circle.clear();
    dfs(1);
    int sum = 0;
    for (int v : circle) {
        lf[v] = count_leaf(v, v);
        sum += lf[v];
        // cout << v << " " << lf[v] << "\n";
    }
    int ans = max(3, sum);
    for (int i = 0; i < circle.size(); i++) {
        int v = circle[i];
        int u = circle[(i + 1) % circle.size()];
        ans = max(ans, sum - lf[u] - lf[v] + 2);
        ans = max(ans, sum - lf[v] + 1);
    }
    cout << ans << "\n";
}

int main() {
    // prep();
    // cout << C(5, 4) << endl;
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int t = 1; cin >> t;
    while (t--) {
        Solve();
    }
}

Details

Tip: Click on the bar to expand more detailed information

Test #1:

score: 100
Accepted
time: 0ms
memory: 6016kb

input:

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

output:

4
3

result:

ok 2 number(s): "4 3"

Test #2:

score: 0
Accepted
time: 97ms
memory: 6736kb

input:

85665
6
3 2
4 1
4 6
2 1
2 6
5 1
7
6 2
6 3
5 1
1 2
2 4
4 7
3 7
7
6 1
6 7
1 4
1 3
7 5
5 3
4 2
7
6 2
7 4
7 5
3 1
3 4
2 5
1 4
7
7 2
2 6
5 4
5 6
5 1
3 1
4 6
7
3 5
3 1
3 7
3 2
5 1
5 4
4 6
7
4 5
4 1
3 6
3 7
6 7
6 1
2 1
7
5 3
7 3
1 4
6 2
6 3
2 3
4 3
7
2 3
2 6
2 4
7 5
3 5
5 1
1 4
7
3 4
3 7
5 6
2 7
4 6
6 7
6 ...

output:

4
3
3
3
3
4
4
5
4
5
4
4
3
4
4
3
4
4
4
4
4
5
3
4
3
4
3
9
4
4
3
4
8
3
98
5
4
3
6
4
4
4
4
3
4
4
4
4
5
3
5
4
3
4
95
4
4
4
5
4
3
4
3
5
4
3
4
3
3
4
4
4
4
4
3
4
4
4
3
3
3
4
4
3
4
4
4
4
4
4
3
3
5
5
4
5
4
3
4
4
3
3
3
5
4
4
4
6
4
5
5
5
4
3
5
4
4
3
4
10
4
3
3
4
4
3
5
4
4
3
5
3
4
4
3
3
3
4
5
98
5
105
4
4
4
3
4
...

result:

ok 85665 numbers

Test #3:

score: 0
Accepted
time: 334ms
memory: 20348kb

input:

30
2229
1066 248
248 881
881 2080
2080 1615
1615 1647
1647 1774
1774 196
196 434
434 390
390 129
129 563
563 63
63 1457
1457 1015
1015 2200
2200 1187
1187 1763
1763 1121
1121 2122
2122 1783
1783 1756
1756 2031
2031 2153
2153 605
605 1778
1778 1287
1287 2062
2062 817
817 194
194 474
474 414
414 1736
...

output:

1092
881
722
1412
37556
638
438
509
273
29198
740
27535
46011
865
444
30031
49564
794
489
469
624
956
1180
17384
50000
715
1291
49920
1465
3

result:

ok 30 numbers