oj.uz

Submission #174404

# Submission time Handle Problem Language Result Execution time Memory
174404 2020-01-06T11:23:29 Z emil_physmath Hard route (IZhO17_road) C++17
52 / 100
 928 ms 108056 KB 
// #define DEBUG
// #define STRESS_TESTING
#define ALL__LL
#include <algorithm>
#include <vector>
#include <iostream>
#include <cstring>
#include <map>
using namespace std;
typedef long long llong;
#ifdef ALL_LL
#define int long long
#endif
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?
        {
#ifdef DEBUG
            if (v == 3)
            {
                cerr << "Good.\tp = " << p << endl;
            }
#endif
            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
}
#ifdef ALL_LL
#undef int
#endif
int main()
#ifdef ALL_LL
#define int long long
#endif
{
    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
}
/*
seed: 78587235
1 2
1 3
3 4
4 5
3 6
6 7
4 8
1 9

8 10
8 8 / right answer
*/

Compilation message

road.cpp: In function 'std::pair<int, int> AC::DFS(int, int, int)':
road.cpp:52:24: 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:75:24: 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:174:18: warning: unused variable 'f' [-Wunused-variable]
             bool f = (p.first == dists[v][0].first);
                  ^
road.cpp:161:107: 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:149:9: 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 23796 KB Output is correct
3 Correct 22 ms 23800 KB Output is correct
4 Correct 22 ms 23800 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 23 ms 23772 KB Output is correct
7 Correct 23 ms 23780 KB Output is correct
8 Correct 23 ms 23800 KB Output is correct
9 Correct 23 ms 23772 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 23 ms 23928 KB Output is correct
12 Correct 23 ms 23804 KB Output is correct
13 Correct 23 ms 23800 KB Output is correct
14 Correct 23 ms 23800 KB Output is correct
15 Correct 24 ms 23800 KB Output is correct
16 Correct 24 ms 23772 KB Output is correct
17 Correct 23 ms 23928 KB Output is correct
18 Correct 23 ms 23800 KB Output is correct
19 Correct 24 ms 23888 KB Output is correct
20 Correct 23 ms 23800 KB Output is correct
21 Correct 24 ms 23876 KB Output is correct
22 Correct 24 ms 23928 KB Output is correct
23 Correct 23 ms 23800 KB Output is correct
24 Correct 23 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 23796 KB Output is correct
3 Correct 22 ms 23800 KB Output is correct
4 Correct 22 ms 23800 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 23 ms 23772 KB Output is correct
7 Correct 23 ms 23780 KB Output is correct
8 Correct 23 ms 23800 KB Output is correct
9 Correct 23 ms 23772 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 23 ms 23928 KB Output is correct
12 Correct 23 ms 23804 KB Output is correct
13 Correct 23 ms 23800 KB Output is correct
14 Correct 23 ms 23800 KB Output is correct
15 Correct 24 ms 23800 KB Output is correct
16 Correct 24 ms 23772 KB Output is correct
17 Correct 23 ms 23928 KB Output is correct
18 Correct 23 ms 23800 KB Output is correct
19 Correct 24 ms 23888 KB Output is correct
20 Correct 23 ms 23800 KB Output is correct
21 Correct 24 ms 23876 KB Output is correct
22 Correct 24 ms 23928 KB Output is correct
23 Correct 23 ms 23800 KB Output is correct
24 Correct 23 ms 23800 KB Output is correct
25 Correct 28 ms 24428 KB Output is correct
26 Correct 28 ms 24568 KB Output is correct
27 Correct 27 ms 24568 KB Output is correct
28 Correct 27 ms 24568 KB Output is correct
29 Correct 27 ms 24568 KB Output is correct
30 Correct 27 ms 24696 KB Output is correct
31 Correct 27 ms 24696 KB Output is correct
32 Correct 28 ms 24572 KB Output is correct
33 Correct 28 ms 24568 KB Output is correct
34 Correct 27 ms 24568 KB Output is correct
35 Correct 27 ms 24568 KB Output is correct
36 Correct 27 ms 24592 KB Output is correct
37 Correct 28 ms 24668 KB Output is correct
38 Correct 28 ms 24832 KB Output is correct
39 Correct 27 ms 24460 KB Output is correct
40 Correct 27 ms 24440 KB Output is correct
41 Correct 28 ms 24408 KB Output is correct
42 Correct 27 ms 24312 KB Output is correct
43 Correct 27 ms 24440 KB Output is correct
44 Correct 27 ms 24312 KB Output is correct
45 Correct 27 ms 24312 KB Output is correct
46 Correct 26 ms 24184 KB Output is correct
47 Correct 27 ms 24312 KB Output is correct
48 Correct 26 ms 24316 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 23796 KB Output is correct
3 Correct 22 ms 23800 KB Output is correct
4 Correct 22 ms 23800 KB Output is correct
5 Correct 22 ms 23800 KB Output is correct
6 Correct 23 ms 23772 KB Output is correct
7 Correct 23 ms 23780 KB Output is correct
8 Correct 23 ms 23800 KB Output is correct
9 Correct 23 ms 23772 KB Output is correct
10 Correct 23 ms 23800 KB Output is correct
11 Correct 23 ms 23928 KB Output is correct
12 Correct 23 ms 23804 KB Output is correct
13 Correct 23 ms 23800 KB Output is correct
14 Correct 23 ms 23800 KB Output is correct
15 Correct 24 ms 23800 KB Output is correct
16 Correct 24 ms 23772 KB Output is correct
17 Correct 23 ms 23928 KB Output is correct
18 Correct 23 ms 23800 KB Output is correct
19 Correct 24 ms 23888 KB Output is correct
20 Correct 23 ms 23800 KB Output is correct
21 Correct 24 ms 23876 KB Output is correct
22 Correct 24 ms 23928 KB Output is correct
23 Correct 23 ms 23800 KB Output is correct
24 Correct 23 ms 23800 KB Output is correct
25 Correct 28 ms 24428 KB Output is correct
26 Correct 28 ms 24568 KB Output is correct
27 Correct 27 ms 24568 KB Output is correct
28 Correct 27 ms 24568 KB Output is correct
29 Correct 27 ms 24568 KB Output is correct
30 Correct 27 ms 24696 KB Output is correct
31 Correct 27 ms 24696 KB Output is correct
32 Correct 28 ms 24572 KB Output is correct
33 Correct 28 ms 24568 KB Output is correct
34 Correct 27 ms 24568 KB Output is correct
35 Correct 27 ms 24568 KB Output is correct
36 Correct 27 ms 24592 KB Output is correct
37 Correct 28 ms 24668 KB Output is correct
38 Correct 28 ms 24832 KB Output is correct
39 Correct 27 ms 24460 KB Output is correct
40 Correct 27 ms 24440 KB Output is correct
41 Correct 28 ms 24408 KB Output is correct
42 Correct 27 ms 24312 KB Output is correct
43 Correct 27 ms 24440 KB Output is correct
44 Correct 27 ms 24312 KB Output is correct
45 Correct 27 ms 24312 KB Output is correct
46 Correct 26 ms 24184 KB Output is correct
47 Correct 27 ms 24312 KB Output is correct
48 Correct 26 ms 24316 KB Output is correct
49 Correct 872 ms 96148 KB Output is correct
50 Correct 881 ms 100088 KB Output is correct
51 Correct 928 ms 103396 KB Output is correct
52 Correct 865 ms 91768 KB Output is correct
53 Incorrect 894 ms 108056 KB Output isn't correct
54 Halted 0 ms 0 KB -