Submission #1125693

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125693		chaoslong	Regions (IOI09_regions)	C++20	100 / 100	3339 ms	36632 KiB

regions

// Calm down.
// Think three times, code twice.
#include "bits/stdc++.h"
#define forr(_a,_b,_c) for(int _a = (_b); _a <= (_c); ++_a)
#define ford(_a,_b,_c) for(int _a = (_b) + 1; _a --> (_c);)
#define forf(_a,_b,_c) for(int _a = (_b); _a < (_c); ++_a)
#define st first
#define nd second
#define ll long long
#define ull unsigned long long
#define pii pair <int,int>
#define pll pair <ll,ll>
#define piii pair <int,pii>
#define vi vector <int>
#define pb push_back
#define mp make_pair
#define all(x) begin(x),end(x)
#define mask(i) (1LL << (i))
#define bit(x, i) (((x) >> (i)) & 1)
#define bp __builtin_popcountll
#define file "test"

using namespace std;
const int N = 2e5 + 5;
const int mod = 1e9 + 7; // 998244353
const ll oo = 1e18;

int n, r, q, tin[N], tout[N], pos[N], timer = 1, h[N], prec[450][N], id[N];
vector<int> a[N];
vector<int> comp[N];

void dfs(int u, int pre) {
    tin[u] = timer;
    pos[timer++] = u;
    comp[h[u]].pb(tin[u]);
    for(int v: a[u]) {
        if(v == pre) continue;
        dfs(v, u);
    }
    tout[u] = timer - 1;
}

void precal(int u, int pre, int cur_r, int dem_cur) {
    if(h[u] == cur_r) dem_cur++;
    for(int v: a[u]) {
        if(v == pre) continue;
        prec[id[cur_r]][h[v]] += dem_cur;
//        cout << cur_r << " " << u << " " << v << " " << prec[id[cur_r]][h[v]] << "\n";
        precal(v, u, cur_r, dem_cur);
    }
}

void to_nho_cau() {
    cin >> n >> r >> q;
    forr(i, 1, n) {
        if(i == 1) {
            int x; cin >> x;
            h[i] = x;
        } else {
            int x, y; cin >> x >> y;
            a[x].pb(i);
            h[i] = y;
        }
    }
    dfs(1, 1);
    int block = (int)(sqrt(n));
    int dem = 1;
    forr(i, 1, r) {
        if(comp[i].size() > block) {
            id[i] = dem++;
            precal(1, 1, i, 0);
        }
    }
    while(q--) {
        int x, y; cin >> x >> y;
        if(id[x]) {
            cout << prec[id[x]][y] << endl;
        } else {
            int ans = 0;
            for(int v: comp[x]) {
                int l = lower_bound(all(comp[y]), v) - comp[y].begin();
                int r = upper_bound(all(comp[y]), tout[pos[v]]) - comp[y].begin(); r--;
                if(l == n+1 || l > r) continue;
                ans += (r - l + 1);
            }
            cout << ans << endl;
        }
    }
}

signed main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    #ifdef LOCAL
        freopen(file".inp","r",stdin);
        freopen(file".out","w",stdout);
    #endif
    int t = 1;
    //cin >> t;
    while(t--) to_nho_cau();
}
/*
1.self check:
2.long long
3.size of array
4.code for testing
5.initializing
6.modulo number
*/
/**
  ∧__∧
（｀•ω• )づ__∧
（つ　 /( •ω•。)
  しーＪ (nnノ) pat pat
**/
/**  /\_/\
*   (= ._.)
*   / >☕ \>💻
**/

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