Submission #649261

#	Time	Username	Problem	Language	Result	Execution time	Memory
649261		vladutpiele	Regions (IOI09_regions)	C++17	55 / 100	2750 ms	54080 KiB

regions

#include <bits/stdc++.h>

#define int long long

using namespace std;

const int nmax = 200000;
const int block = 1000;

long long n, r, q;
int region[nmax + 5], cntRegion[nmax + 5];
int bigRegion[nmax + 5], cntBigRegion, bigIdx[nmax + 5];
int smallRegion[nmax + 5], cntSmallRegion, smallIdx[nmax + 5];
long long cntAbove[nmax + 5], sol[205][25005], sumePartiale[nmax + 5];
long long precalc[205][25005];
int cntTimp, newtime;
int stiva[nmax + 5];
vector<pair<int, int>> lista[25005];
pair<int, int> timp[nmax + 5];
vector<int> nodesFromRegion[nmax + 5];
vector<int> g[nmax + 5];

void dfs(int fiu, int tata)
{
    newtime++;
    lista[region[fiu]].push_back(make_pair(fiu, newtime));
    timp[fiu].first = ++cntTimp;
    /// cntAbove[i] -> numarul de noduri de regiunea i(care este o regiune de tip BIG), care sunt stramosi ai nodului curent
    if(bigIdx[region[fiu]] != 0)
    {
        cntAbove[bigIdx[region[fiu]]] ++;
    }
    for(int i = 1; i <= cntBigRegion; i ++)
    {
        sol[bigIdx[bigRegion[i]]][region[fiu]] += 1LL * cntAbove[bigIdx[region[fiu]]];
    }
    for(auto it : g[fiu])
    {
        if(it == tata)
        {
            continue;
        }
        dfs(it, fiu);
    }
    if(bigIdx[region[fiu]] != 0)
    {
        cntAbove[bigIdx[region[fiu]]] ++;
    }
    newtime++;
    lista[region[fiu]].push_back(make_pair(fiu, newtime));
    timp[fiu].second = cntTimp;
}

signed main()
{
    cin >> n >> r >> q;
    cin >> region[1];
    cntRegion[region[1]] ++;
    for(int i = 2; i <= n; i ++)
    {
        int p;
        cin >> p >> region[i];
        g[p].push_back(i);
        g[i].push_back(p);
        cntRegion[region[i]] ++;
        nodesFromRegion[region[i]].push_back(i);
    }
    for(int i = 1; i <= r; i ++)
    {
        if(cntRegion[i] >= block)
        {
            bigRegion[++cntBigRegion] = i;
            bigIdx[i] = cntBigRegion;
        }
        else
        {
            smallRegion[++cntSmallRegion] = i;
            smallIdx[i] = cntSmallRegion;
        }
    }

    /// in dfs calculez pentru tipurile 1 si 2, cand regiunea de sus este de tip BIG

    dfs(1, 0);

    /// imi propun sa calculez pentru tipul 3, cand regiunea de jos este de tip BIG, iar regiunea de sus este de tip SMALL

    for(long long i = 1; i <= r; i ++)
    {
        if(bigIdx[i] == 0)
        {
            continue;
        }
        for(auto it : nodesFromRegion[i])
        {
            sumePartiale[timp[it].first] ++;
        }
        for(long long j = 1; j <= n; j ++)
        {
            sumePartiale[j] += 1LL * sumePartiale[j - 1];
        }
        for(long long j = 1; j <= cntSmallRegion; j ++)
        {
            for(auto it : nodesFromRegion[smallRegion[i]])
            {
                precalc[bigIdx[i]][j] += 1LL * (sumePartiale[timp[it].second] - sumePartiale[timp[it].first] - 1);
            }
        }
        for(long long j = 1; j <= n; j ++)
        {
            sumePartiale[j] = 0;
        }
    }

    while(q--)
    {
        long long a, b;
        cin >> a >> b;
        if(bigIdx[a] != 0)
        {
            /// cand regiunea de sus e de tip BIG
            cout << sol[bigIdx[a]][b] << '\n';
        }
        else
        {
            if(bigIdx[b] != 0)
            {
                /// cand regiunea de jos e BIG, dar cea de sus e SMALL
                cout << precalc[bigIdx[b]][smallIdx[a]] << '\n';
            }
            else
            {
                long long i = 0, j = 0, vf = 0;
                long long deschise = 0, answer = 0;
                while(i < lista[a].size() && j < lista[b].size())
                {
                    pair<int, int> frst = lista[a][i];
                    pair<int, int> scnd = lista[b][j];
                    if(frst.second < scnd.second)
                    {
                        if(vf && frst.first == stiva[vf])
                        {
                            vf--;
                            deschise--;
                        }
                        else
                        {
                            stiva[++vf] = frst.first;
                            deschise++;
                        }
                        i++;
                    }
                    else
                    {
                        if(vf && scnd.first == stiva[vf])
                        {
                            vf--;
                        }
                        else
                        {
                            answer += 1LL * deschise;
                            stiva[++vf] = scnd.first;
                        }
                        j++;
                    }
                }
                cout << answer << '\n';
            }
        }
    }
    return 0;
}

Compilation message (stderr)

regions.cpp: In function 'int main()':
regions.cpp:135:25: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  135 |                 while(i < lista[a].size() && j < lista[b].size())
      |                       ~~^~~~~~~~~~~~~~~~~
regions.cpp:135:48: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  135 |                 while(i < lista[a].size() && j < lista[b].size())
      |                                              ~~^~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 40 / 85