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Submission #519862

# Submission time Handle Problem Language Result Execution time Memory
519862 2022-01-27T12:47:40 Z Dasha_Gnedko Hard route (IZhO17_road) C++17
19 / 100
 2000 ms 24236 KB 
#include <bits/stdc++.h>

//#include <ext/pb_ds/detail/standard_policies.hpp>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>

//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx2")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4")

using namespace std;

//using namespace __gnu_pbds;
//template <typename T> using ordered_set = tree <T, null_type, less < T >, rb_tree_tag, tree_order_statistics_node_update>;

mt19937 gen(time(0));

#define ll long long
#define ld long double
#define pb push_back
#define F first
#define S second
#define TIME clock() * 1.0 / CLOCKS_PER_SEC
#define sz(a) int32_t(a.size())
#define endl '\n'
//#define int long long

const int N = 1e6 + 100;
const int M = 31;
const int mod = 1e9 + 7;
const int inf = 1e9 + 7;

vector < int > g[N];
int leaf[N], ra[N], h[N], up[N], pred[N];

void DFS(int v, int pr)
{
    pred[v] = pr;
    h[v] = 0;
    for(auto to: g[v])
    {
        if (to == pr) continue;
        DFS(to, v);
        h[v] = max(h[v], h[to] + 1);
    }
}

void dfs(int v, int pr, int c)
{
    int mx = -2, sr = -2;
    for(auto to: g[v])
    {
        if (to == pr) continue;
        if (h[to] >= mx)
        {
            sr = mx;
            mx = h[to];
        }
        else sr = max(sr, h[to]);
    }
    up[v] = c;
    for(auto to: g[v])
    {
        if (to == pr) continue;
        if (h[to] == mx) dfs(to, v, max(c + 1, sr + 2));
        else dfs(to, v, max(c + 1, mx + 2));
    }
}

ll get_mx(int n)
{
    DFS(0, 0);
    dfs(0, 0, 0);
    ll ans = 0;
    for(int v = 0; v < n; v++)
    {
        vector < int > ve;
        if (up[v]) ve.pb(up[v]);
        for(auto to: g[v])
        {
            if (to == pred[v]) continue;
            ve.pb(h[to] + 1);
        }
        sort(ve.rbegin(), ve.rend());
        while (sz(ve) > 3) ve.pop_back();
        if (sz(ve) == 3)
        {
//            cerr << v + 1 << " " << ve[0] << " " << ve[1] << " " << ve[2] << endl;
            ans = max(ans, 1ll * (ve[1] + ve[2]) * ve[0]);
            ans = max(ans, 1ll * (ve[0] + ve[2]) * ve[1]);
            ans = max(ans, 1ll * (ve[0] + ve[1]) * ve[2]);
        }
    }
    return ans;
}

int calc(int a, int b, int n)
{
    vector < int > pr(n);
    for(int i = 0; i < n; i++)
        ra[i] = -1;
    ra[a] = 0;
    queue < int > q;
    q.push(a);
    while (!q.empty())
    {
        int v = q.front();
        q.pop();
        for(auto to: g[v])
        {
            if (ra[to] == -1)
            {
                ra[to] = ra[v] + 1;
                pr[to] = v;
                q.push(to);
            }
        }
    }
    int mx = ra[b];
    while (1)
    {
        ra[b] = 0;
        q.push(b);
        if (b == a) break;
        b = pr[b];
    }
    for(int i = 0; i < n; i++)
        if (ra[i] != 0) ra[i] = -1;
    while (!q.empty())
    {
        int v = q.front();
        q.pop();
        for(auto to: g[v])
        {
            if (ra[to] == -1)
            {
                ra[to] = ra[v] + 1;
                pr[to] = v;
                q.push(to);
            }
        }
    }
    int cnt = 0;
    for(int i = 0; i < n; i++)
        cnt = max(cnt, ra[i]);
    return cnt * mx;
}

int32_t main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#else
//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);
#endif // LOCAL

    int n;
    cin >> n;
    for(int i = 0; i < n - 1; i++)
    {
        int x, y;
        cin >> x >> y;
        x--; y--;
        g[x].pb(y);
        g[y].pb(x);
    }
    for(int i = 0; i < n; i++)
        leaf[i] = (sz(g[i]) == 1);
    ll mx = get_mx(n), k = 0;
    for(int i = 0; i < n; i++)
    {
        if (!leaf[i]) continue;
        for(int j = i + 1; j < n; j++)
        {
            if (!leaf[j]) continue;
            int c = calc(i, j, n);
            k += (c == mx);
        }
    }
    cout << mx << " " << k;
}

Subtask #1
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23756 KB Output is correct
2 Correct 12 ms 23784 KB Output is correct
3 Correct 12 ms 23756 KB Output is correct
4 Correct 12 ms 23756 KB Output is correct
5 Correct 15 ms 23732 KB Output is correct
6 Correct 13 ms 23788 KB Output is correct
7 Correct 14 ms 23840 KB Output is correct
8 Correct 13 ms 23756 KB Output is correct
9 Correct 14 ms 23756 KB Output is correct
10 Correct 15 ms 23820 KB Output is correct
11 Correct 16 ms 23796 KB Output is correct
12 Correct 16 ms 23744 KB Output is correct
13 Correct 15 ms 23744 KB Output is correct
14 Correct 15 ms 23744 KB Output is correct
15 Correct 15 ms 23816 KB Output is correct
16 Correct 13 ms 23756 KB Output is correct
17 Correct 13 ms 23844 KB Output is correct
18 Correct 12 ms 23756 KB Output is correct
19 Correct 13 ms 23756 KB Output is correct
20 Correct 13 ms 23756 KB Output is correct
21 Correct 12 ms 23824 KB Output is correct
22 Correct 12 ms 23756 KB Output is correct
23 Correct 12 ms 23756 KB Output is correct
24 Correct 23 ms 23844 KB Output is correct

Subtask #2
0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23756 KB Output is correct
2 Correct 12 ms 23784 KB Output is correct
3 Correct 12 ms 23756 KB Output is correct
4 Correct 12 ms 23756 KB Output is correct
5 Correct 15 ms 23732 KB Output is correct
6 Correct 13 ms 23788 KB Output is correct
7 Correct 14 ms 23840 KB Output is correct
8 Correct 13 ms 23756 KB Output is correct
9 Correct 14 ms 23756 KB Output is correct
10 Correct 15 ms 23820 KB Output is correct
11 Correct 16 ms 23796 KB Output is correct
12 Correct 16 ms 23744 KB Output is correct
13 Correct 15 ms 23744 KB Output is correct
14 Correct 15 ms 23744 KB Output is correct
15 Correct 15 ms 23816 KB Output is correct
16 Correct 13 ms 23756 KB Output is correct
17 Correct 13 ms 23844 KB Output is correct
18 Correct 12 ms 23756 KB Output is correct
19 Correct 13 ms 23756 KB Output is correct
20 Correct 13 ms 23756 KB Output is correct
21 Correct 12 ms 23824 KB Output is correct
22 Correct 12 ms 23756 KB Output is correct
23 Correct 12 ms 23756 KB Output is correct
24 Correct 23 ms 23844 KB Output is correct
25 Execution timed out 2063 ms 24236 KB Time limit exceeded
26 Halted 0 ms 0 KB -

Subtask #3
0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23756 KB Output is correct
2 Correct 12 ms 23784 KB Output is correct
3 Correct 12 ms 23756 KB Output is correct
4 Correct 12 ms 23756 KB Output is correct
5 Correct 15 ms 23732 KB Output is correct
6 Correct 13 ms 23788 KB Output is correct
7 Correct 14 ms 23840 KB Output is correct
8 Correct 13 ms 23756 KB Output is correct
9 Correct 14 ms 23756 KB Output is correct
10 Correct 15 ms 23820 KB Output is correct
11 Correct 16 ms 23796 KB Output is correct
12 Correct 16 ms 23744 KB Output is correct
13 Correct 15 ms 23744 KB Output is correct
14 Correct 15 ms 23744 KB Output is correct
15 Correct 15 ms 23816 KB Output is correct
16 Correct 13 ms 23756 KB Output is correct
17 Correct 13 ms 23844 KB Output is correct
18 Correct 12 ms 23756 KB Output is correct
19 Correct 13 ms 23756 KB Output is correct
20 Correct 13 ms 23756 KB Output is correct
21 Correct 12 ms 23824 KB Output is correct
22 Correct 12 ms 23756 KB Output is correct
23 Correct 12 ms 23756 KB Output is correct
24 Correct 23 ms 23844 KB Output is correct
25 Execution timed out 2063 ms 24236 KB Time limit exceeded
26 Halted 0 ms 0 KB -