Submission #298961

#	Time	Username	Problem	Language	Result	Execution time	Memory
298961		jovan_b	Regions (IOI09_regions)	C++17	55 / 100	8026 ms	129028 KiB

regions

#include <bits/stdc++.h>
using namespace std;

typedef long long ll;

int LIM = 500;
int in[200005];
int out[200005];
int region[200005];
int parent[200005];
int cnt[200005];
vector <int> graf[200005];

int gore[25005][505];
int dole[25005][505];

int sada[25005];
int rev[25005];
int compress[25005];
int ccomp;

int r;

int tajm;

vector <pair <int, int>> svi[25005];
vector <int> ins[25005];

void dfs(int v){

    in[v] = ++tajm;
    sada[region[v]]++;
    if(compress[region[v]]){
        for(int i=1; i<=r; i++){
            dole[i][compress[region[v]]] += sada[region[v]];
        }
        dole[region[v]][compress[region[v]]]--;
        gore[region[v]][compress[region[v]]]--;
    }
    for(int i=1; i<=ccomp; i++){
        gore[region[v]][i] += sada[rev[i]];
    }
    for(auto c : graf[v]){
        dfs(c);
    }
    sada[region[v]]--;
    out[v] = tajm;
    svi[region[v]].push_back({in[v], 1});
    svi[region[v]].push_back({out[v]+1, -1});
    ins[region[v]].push_back(in[v]);
}

int main(){
    ios_base::sync_with_stdio(false), cin.tie(0);

    int n, q;
    cin >> n >> r >> q;
    cin >> region[1];
    cnt[region[1]]++;
    for(int i=2; i<=n; i++){
        cin >> parent[i] >> region[i];
        cnt[region[i]]++;
        graf[parent[i]].push_back(i);
    }
    for(int i=1; i<=r; i++){
        if(cnt[i] <= LIM) continue;
        compress[i] = ++ccomp;
        rev[ccomp] = i;
    }
    dfs(1);
    for(int i=1; i<=r; i++) sort(svi[i].begin(), svi[i].end());
    for(int i=1; i<=r; i++) sort(ins[i].begin(), ins[i].end());
    while(q--){
        int a, b;
        cin >> a >> b;
        if(cnt[a] > LIM){
            cout << gore[b][compress[a]] << endl;
            continue;
        }
        if(cnt[b] > LIM){
            cout << dole[a][compress[b]] << endl;
            continue;
        }
        int k = svi[a].size();
        int j = -1;
        int tren = 0;
        ll res = 0;
        for(auto c : ins[b]){
            while(j < k-1 && c >= svi[a][j+1].first){
                j++;
                tren += svi[a][j].second;
            }
            res += tren;
        }
        cout << res << endl;
    }

    return 0;
}

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