oj.uz

Submission #172283

# Submission time Handle Problem Language Result Execution time Memory
172283 2019-12-31T23:46:46 Z emil_physmath Hard route (IZhO17_road) C++17
52 / 100
 868 ms 111396 KB 
// #define DEBUG
// #define STRESS_TESTING
#include <algorithm>
#include <vector>
#include <iostream>
#include <cstring>
#include <map>
using namespace std;
typedef long long llong;
const int maxN = 500005;

vector<int> nei[maxN];
pair<int, int> ray[maxN][3];
map<llong, llong> ans;
vector<pair<int, int>> dists[maxN];

namespace AC
{
    int n;
    pair<int, int> maxdist[maxN];
    bool used[maxN];

    void MaxDist(int u);
    pair<int, int> DFS(int u, int dep, int dist);
    void Solve(int n_)
    {
        n = n_;
        pair<int, int> ans(0, 0);
        for (int u=1; u<=n; u++)
            if (nei[u].size()==1)
            {
                memset(used+1, 0, n*sizeof(bool));
                MaxDist(u);
                memset(used+1, 0, n*sizeof(bool));
                pair<int, int> curAns=DFS(u, 0, 0);
                if (curAns.first>ans.first) ans=curAns;
                else if (curAns.first==ans.first) ans.second+=curAns.second;
            }
        cout<<ans.first<<' '<<ans.second/2<<'\n';
    }

    pair<int, int> DFS(int u, int dep, int dist)
    {
        used[u]=true;
        if (nei[u].size()==1 && used[nei[u][0]])
            return make_pair(dep*dist, 1);
        pair<int, int> ans(0, 0);
        for (int i=0; i<nei[u].size(); i++)
        {
            int to=nei[u][i];
            if (!used[to])
            {
                pair<int, int> curAns;
                if (maxdist[u].first==maxdist[to].first+1)
                    curAns=DFS(to, dep+1, max(dist, maxdist[u].second));
                else
                    curAns=DFS(to, dep+1, max(dist, maxdist[u].first));

                if (curAns.first>ans.first) ans=curAns;
                else if (curAns.first==ans.first) ans.second+=curAns.second;
            }
        }
        return ans;
    }

    void MaxDist(int u)
    {
        used[u]=true;
        maxdist[u]=make_pair(0, 0);
        if (nei[u].size()==1 && used[nei[u][0]]) return;
        for (int i=0; i<nei[u].size(); i++)
        {
            int to=nei[u][i];
            if (!used[to])
            {
                MaxDist(to);
                int temp=maxdist[to].first+1;
                if (temp>maxdist[u].first)
                {
                    swap(maxdist[u].first, maxdist[u].second);
                    maxdist[u].first=temp;
                }
                else if (temp>maxdist[u].second)
                    maxdist[u].second=temp;
            }
        }
    }
};
inline ostream& operator<<(ostream& ostr, const pair<int, int>& a)
{
    return ostr << "{" << a.first << ", " << a.second << "}";
}
void Maximize(pair<int, int>* a, pair<int, int> x)
{
    if (a[0].first == x.first)
        a[0].second += x.second;
    else if (a[1].first == x.first)
        a[1].second += x.second;
    else if (a[2].first == x.first)
        a[2].second += x.second;
    else if (x.first > a[2].first)
    {
        a[2] = x;
        sort(a, a + 3, greater<pair<int, int>>());
    }
}
void SetDown(int v, int par)
{
    fill(ray[v], ray[v] + 3, make_pair(0, 0));
    ray[v][0] = {0, 1};
    for (int to: nei[v])
        if (to != par)
        {
            SetDown(to, v);
            int val, cnt;
            Maximize(ray[v], {(val = ray[to][0].first + 1), (cnt = ray[to][0].second/*1*/)});
            if (val) dists[v].push_back({val, cnt});
        }
}
void SetUp(int v, int par)
{
    for (int to: nei[v])
        if (to != par)
        {
            // Set up[to].
            int val = 0, cnt = 0;
            if (ray[v][0].first == ray[to][0].first + 1 && ray[v][0].second == ray[to][0].second)
                Maximize(ray[to], {(val = ray[v][1].first + 1), (cnt = ray[v][1].second/*1*/)});
            else if (ray[v][0].first == ray[to][0].first + 1)
                Maximize(ray[to], {(val = ray[v][0].first + 1), (cnt = ray[v][0].second - ray[to][0].second/*1*/)});
            else
                Maximize(ray[to], {(val = ray[v][0].first + 1), (cnt = ray[v][0].second)});
            if (val) dists[to].push_back({val, cnt});
            SetUp(to, v);
        }
    sort(dists[v].begin(), dists[v].end(), greater<pair<int, int>>());
#ifdef DEBUG
    cerr << "v: " << v << "\tdists: " << dists[v][0] << ' ';
    if (dists[v].size() >= 2) cout << dists[v][1];
    if (dists[v].size() >= 3) cout << ' ' << dists[v][2];
    cout << endl;
#endif
    if (dists[v].size() < 3) return;
    bool eq = (dists[v][1].first == dists[v][2].first);
    int cnt[2];
    for (int i = 0; i < 3; ++i)
    {
        if (ray[v][i].first == dists[v][1].first)
            cnt[0] = ray[v][i].second;
        if (ray[v][i].first == dists[v][2].first)
            cnt[1] = ray[v][i].second;
    }
    llong delta;
    if (eq)
        ans[dists[v][0].first * (dists[v][1].first + dists[v][2].first)] += (delta = (cnt[0] * (cnt[0] - 1LL)) / 2LL);
    else
        ans[dists[v][0].first * (dists[v][1].first + dists[v][2].first)] += (delta = (llong)cnt[0] * cnt[1]);
    // Subtract x * (x - 1) / 2 for x = rays going to the same `to`
    for (auto p: dists[v])
    {
        llong dlt;
        if ((p.first == dists[v][1].first || p.first == dists[v][2].first) && dists[v][1].first == dists[v][2].first) // erkrord paymany petqa?
        {
            bool f = (p.first == dists[v][0].first);
            if (f) --p.second;
            ans[dists[v][0].first * (dists[v][1].first + dists[v][2].first)] -=
            (dlt = (p.second * (p.second - 1LL)) / 2LL);
            if (f) ++p.second;
#ifdef DEBUG
            cerr << "v: " << v << "\tdelta = -" << dlt << endl;
#endif
        }
    }
#ifdef DEBUG
    cerr << "v: " << v << "\tdelta = " << delta << endl;
#endif
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    int n;
    // cin >> n;
    // n = rand() % 20 + 1;
#ifndef STRESS_TESTING
    cin >> n;
#endif
#ifdef STRESS_TESTING
    n = 9;
    int seed;
    cin >> seed;
    srand(seed);
#endif
    // cerr << n << endl;
    for (int i = 1; i < n; ++i)
    {
        int u, v;
#ifndef STRESS_TESTING
        cin >> u >> v;
#else
        v = i + 1;
        u = rand() % i + 1;
        cerr << u << ' ' << v << endl;
#endif
        nei[u].push_back(v);
        nei[v].push_back(u);
    }
    SetDown(1, -1);
    /*for (int v = 1; v <= n; ++v)
        cerr << v << ": " << ray[v][0] << ' ' << ray[v][1] << ' ' << ray[v][2] << endl;*/
    SetUp(1, -1);
#ifdef DEBUG
    for (int v = 1; v <= n; ++v)
    {
        cerr << v << ": " << ray[v][0] << ' ' << ray[v][1] << ' ' << ray[v][2] << endl;
    }
    for (auto it: ans)
        cerr << it << endl;
#endif
    if (ans.size())
        cout << ans.rbegin()->first << ' ' << ans.rbegin()->second;
    else
        cout << "0 1";
#ifdef STRESS_TESTING
    cout << endl;
    AC::Solve(n);
#endif
}
/*
// new
9
1 2
1 3
2 4
3 5
4 6
6 7
3 8
1 9

12 1
12 2 // right answer

// old
9
1 2
2 3
2 4
3 5
2 6
2 7
3 8
7 9

6 9
6 10 // right answer



// old
9
1 2
2 3
3 4
3 5
5 6
4 7
2 8
6 9
12 3
12 2 // right answer
*/

Compilation message

road.cpp: In function 'std::pair<int, int> AC::DFS(int, int, int)':
road.cpp:48:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i=0; i<nei[u].size(); i++)
                       ~^~~~~~~~~~~~~~
road.cpp: In function 'void AC::MaxDist(int)':
road.cpp:71:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i=0; i<nei[u].size(); i++)
                       ~^~~~~~~~~~~~~~
road.cpp: In function 'void SetUp(int, int)':
road.cpp:157:107: warning: 'cnt[1]' may be used uninitialized in this function [-Wmaybe-uninitialized]
         ans[dists[v][0].first * (dists[v][1].first + dists[v][2].first)] += (delta = (llong)cnt[0] * cnt[1]);
                                                                                                      ~~~~~^
road.cpp:145:9: warning: 'cnt[0]' may be used uninitialized in this function [-Wmaybe-uninitialized]
     int cnt[2];
         ^~~

Subtask #1
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23800 KB Output is correct
2 Correct 22 ms 23800 KB Output is correct
3 Correct 22 ms 23804 KB Output is correct
4 Correct 22 ms 23800 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 22 ms 23800 KB Output is correct
7 Correct 22 ms 23928 KB Output is correct
8 Correct 22 ms 23800 KB Output is correct
9 Correct 23 ms 23928 KB Output is correct
10 Correct 22 ms 23800 KB Output is correct
11 Correct 22 ms 23800 KB Output is correct
12 Correct 22 ms 23800 KB Output is correct
13 Correct 22 ms 23800 KB Output is correct
14 Correct 22 ms 23800 KB Output is correct
15 Correct 22 ms 23800 KB Output is correct
16 Correct 22 ms 23800 KB Output is correct
17 Correct 22 ms 23800 KB Output is correct
18 Correct 23 ms 23804 KB Output is correct
19 Correct 23 ms 23800 KB Output is correct
20 Correct 26 ms 23800 KB Output is correct
21 Correct 22 ms 23800 KB Output is correct
22 Correct 28 ms 23800 KB Output is correct
23 Correct 26 ms 23800 KB Output is correct
24 Correct 27 ms 23800 KB Output is correct

Subtask #2
33.0 / 33.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23800 KB Output is correct
2 Correct 22 ms 23800 KB Output is correct
3 Correct 22 ms 23804 KB Output is correct
4 Correct 22 ms 23800 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 22 ms 23800 KB Output is correct
7 Correct 22 ms 23928 KB Output is correct
8 Correct 22 ms 23800 KB Output is correct
9 Correct 23 ms 23928 KB Output is correct
10 Correct 22 ms 23800 KB Output is correct
11 Correct 22 ms 23800 KB Output is correct
12 Correct 22 ms 23800 KB Output is correct
13 Correct 22 ms 23800 KB Output is correct
14 Correct 22 ms 23800 KB Output is correct
15 Correct 22 ms 23800 KB Output is correct
16 Correct 22 ms 23800 KB Output is correct
17 Correct 22 ms 23800 KB Output is correct
18 Correct 23 ms 23804 KB Output is correct
19 Correct 23 ms 23800 KB Output is correct
20 Correct 26 ms 23800 KB Output is correct
21 Correct 22 ms 23800 KB Output is correct
22 Correct 28 ms 23800 KB Output is correct
23 Correct 26 ms 23800 KB Output is correct
24 Correct 27 ms 23800 KB Output is correct
25 Correct 29 ms 24440 KB Output is correct
26 Correct 30 ms 24568 KB Output is correct
27 Correct 27 ms 24696 KB Output is correct
28 Correct 25 ms 24696 KB Output is correct
29 Correct 27 ms 24696 KB Output is correct
30 Correct 26 ms 24756 KB Output is correct
31 Correct 26 ms 24696 KB Output is correct
32 Correct 27 ms 24668 KB Output is correct
33 Correct 26 ms 24568 KB Output is correct
34 Correct 25 ms 24568 KB Output is correct
35 Correct 26 ms 24568 KB Output is correct
36 Correct 26 ms 24568 KB Output is correct
37 Correct 26 ms 24696 KB Output is correct
38 Correct 26 ms 24952 KB Output is correct
39 Correct 32 ms 24568 KB Output is correct
40 Correct 31 ms 24440 KB Output is correct
41 Correct 30 ms 24440 KB Output is correct
42 Correct 26 ms 24312 KB Output is correct
43 Correct 26 ms 24312 KB Output is correct
44 Correct 31 ms 24316 KB Output is correct
45 Correct 26 ms 24316 KB Output is correct
46 Correct 25 ms 24184 KB Output is correct
47 Correct 26 ms 24312 KB Output is correct
48 Correct 25 ms 24440 KB Output is correct

Subtask #3
0 / 48.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23800 KB Output is correct
2 Correct 22 ms 23800 KB Output is correct
3 Correct 22 ms 23804 KB Output is correct
4 Correct 22 ms 23800 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 22 ms 23800 KB Output is correct
7 Correct 22 ms 23928 KB Output is correct
8 Correct 22 ms 23800 KB Output is correct
9 Correct 23 ms 23928 KB Output is correct
10 Correct 22 ms 23800 KB Output is correct
11 Correct 22 ms 23800 KB Output is correct
12 Correct 22 ms 23800 KB Output is correct
13 Correct 22 ms 23800 KB Output is correct
14 Correct 22 ms 23800 KB Output is correct
15 Correct 22 ms 23800 KB Output is correct
16 Correct 22 ms 23800 KB Output is correct
17 Correct 22 ms 23800 KB Output is correct
18 Correct 23 ms 23804 KB Output is correct
19 Correct 23 ms 23800 KB Output is correct
20 Correct 26 ms 23800 KB Output is correct
21 Correct 22 ms 23800 KB Output is correct
22 Correct 28 ms 23800 KB Output is correct
23 Correct 26 ms 23800 KB Output is correct
24 Correct 27 ms 23800 KB Output is correct
25 Correct 29 ms 24440 KB Output is correct
26 Correct 30 ms 24568 KB Output is correct
27 Correct 27 ms 24696 KB Output is correct
28 Correct 25 ms 24696 KB Output is correct
29 Correct 27 ms 24696 KB Output is correct
30 Correct 26 ms 24756 KB Output is correct
31 Correct 26 ms 24696 KB Output is correct
32 Correct 27 ms 24668 KB Output is correct
33 Correct 26 ms 24568 KB Output is correct
34 Correct 25 ms 24568 KB Output is correct
35 Correct 26 ms 24568 KB Output is correct
36 Correct 26 ms 24568 KB Output is correct
37 Correct 26 ms 24696 KB Output is correct
38 Correct 26 ms 24952 KB Output is correct
39 Correct 32 ms 24568 KB Output is correct
40 Correct 31 ms 24440 KB Output is correct
41 Correct 30 ms 24440 KB Output is correct
42 Correct 26 ms 24312 KB Output is correct
43 Correct 26 ms 24312 KB Output is correct
44 Correct 31 ms 24316 KB Output is correct
45 Correct 26 ms 24316 KB Output is correct
46 Correct 25 ms 24184 KB Output is correct
47 Correct 26 ms 24312 KB Output is correct
48 Correct 25 ms 24440 KB Output is correct
49 Correct 826 ms 99100 KB Output is correct
50 Correct 859 ms 103644 KB Output is correct
51 Correct 868 ms 107204 KB Output is correct
52 Correct 831 ms 93972 KB Output is correct
53 Incorrect 865 ms 111396 KB Output isn't correct
54 Halted 0 ms 0 KB -