Submission #649643

#	Time	Username	Problem	Language	Result	Execution time	Memory
649643		mychecksedad	Regions (IOI09_regions)	C++17	90 / 100	3972 ms	131072 KiB

regions

/* Author : Mychecksdead */
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 1e5+10, F = 2147483646, K = 20;


int n, q, r, a[N], ans[505][505], tin[N], tout[N], timer = 0;
vector<int> g[N], R[N], posin[N], posout[N];
vector<pair<int, int>> path;
map<pair<int, int>, pair<bool, int>> m;
void dfs(int v, int p){
    bool ok = 1;
    for(int u: g[v]){
        if(u == p) continue;
        dfs(u, v);
        if(ok){
            ok = 0;
            R[v].swap(R[u]);
            continue;
        }
        for(int j = 1; j <= r; ++j) R[v][j] += R[u][j];
        R[u].clear();
    }
    if(ok) R[v].resize(r + 1);
    for(int j = 1; j <= r; ++j) ans[a[v]][j] += R[v][j];
    R[v][a[v]]++;    
}
void dfs1(int v, int p){
    path.pb({v, 1});
    tin[v] = timer++;
    R[a[v]].pb(v);
    for(int u: g[v]){
        if(u == p) continue;
        dfs1(u, v);
    }
    path.pb({v, 0});
    tout[v] = timer++;
}

void solve(){
    cin >> n >> r >> q;
    cin >> a[1];
    for(int i = 2; i <= n; ++i){
        int x; cin >> x >> a[i];
        g[x].pb(i);
        g[i].pb(x);
    }
    if(r <= 500){
        for(int i = 0; i <= r; ++i) for(int j = 0; j <= r; ++j) ans[i][j] = 0;
        dfs(1, 1);
        for(;q--;){
            int a, b; cin >> a >> b;
            cout << ans[a][b] << endl;
        }
    }else{
        dfs1(1, 1);
        for(int j = 0; j < path.size(); ++j){
            if(path[j].second == 1)
                posin[a[path[j].first]].pb(j);
            else
                posout[a[path[j].first]].pb(j);
        }
        for(;q--;){
            int a, b; cin >> a >> b;
            if(m[{a, b}].first){
                cout << m[{a, b}].second << endl;
                continue;
            }
            int ans = 0;
            if(R[a].size() < R[b].size())
                for(int v: R[a]){
                    ans += upper_bound(all(posin[b]), tout[v]) - upper_bound(all(posin[b]), tin[v]);
                }
            else
                for(int v: R[b]){
                    ans += (upper_bound(all(posin[a]), tin[v]) - posin[a].begin()) - (upper_bound(all(posout[a]), tin[v]) - posout[a].begin());
                }
            cout << ans << endl;
            m[{a, b}] = {1, ans};
        }
    }
}





int main(){
    cin.tie(0); ios::sync_with_stdio(0);
    int T = 1, aa;
    // cin >> T;aa=T;
    while(T--){
        // cout << "Case #" << aa-T << ": ";
        solve();
        // cout << '\n';
    }
    return 0;
 
}

Compilation message (stderr)

regions.cpp: In function 'void solve()':
regions.cpp:68:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |         for(int j = 0; j < path.size(); ++j){
      |                        ~~^~~~~~~~~~~~~
regions.cpp: In function 'int main()':
regions.cpp:101:16: warning: unused variable 'aa' [-Wunused-variable]
  101 |     int T = 1, aa;
      |                ^~

• Subtask 1: 15 / 15
• Subtask 2: 75 / 85