Submission #1285096

#	Time	Username	Problem	Language	Result	Execution time	Memory
1285096		souvenir_vayne	Regions (IOI09_regions)	C++20	50 / 100	8045 ms	185516 KiB

regions

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <chrono>
#define pb push_back
#define INF 0x3f3f3f3f
#define LINF 0x3f3f3f3f3f3f3f3f
#define endl '\n'
#define ll long long
#define f first
#define fin cin
#define fout cout
#define s second
#define FAST cin.tie(0), cout.tie(0), ios::sync_with_stdio(0)
#define debug(x) cerr << "DEBUG " << x << endl
#define debug2(x, y) cerr << "DEBUG " << x << " " << y << endl
#define debug3(x, y, z) cerr << "DEBUG " << x << " " << y << " " << z << endl
#define debug4(x, y, z, o) cerr << "DEBUG " << x << " " << y << " " << z << " " << o << endl
#define all(x) x.begin(), x.end()
#define left esquerda
#define lb lower_bound
#define right direita
using namespace std;
void setIO(string s) {
    ios_base::sync_with_stdio(0); cin.tie(0);
    freopen((s+".in").c_str(),"r",stdin);
    freopen((s+".out").c_str(),"w",stdout);
}
typedef pair<ll, ll> pii;
typedef vector<vector<char>> mat;
typedef pair<int, string> pis;
const ll mod = 1e9 + 7, MAXN = 2e5 + 5;
typedef vector<int> vi;
typedef pair<int, pair<int, int>> piii;

const int N = 2e5;  // limit for array size
int t[2 * N];
int n;

void modify(int p, int value) {  // set value at position p
  for (t[p += n] = value; p > 1; p >>= 1) t[p>>1] = t[p] + t[p^1];
}

int query(int l, int r) {  // sum on interval [l, r)
  int res = 0;
  for (l += n, r += n; l < r; l >>= 1, r >>= 1) {
    if (l&1) res += t[l++];
    if (r&1) res += t[--r];
  }
  return res;
}

void solve() {
    int r, q;
    cin >> n >> r >> q;
    vector<vector<int>> rs(r + 5), g(n + 5);
    vector<int> rr(n + 5);

    int rc;
    cin >> rc;
    rr[1] = rc;
    rs[rc].push_back(1);

    for(int i = 2; i <= n; i++) {
        int p, cr;
        cin >> p >> cr;
        rr[i] = cr;
        g[p].push_back(i);
        rs[cr].push_back(i);
    }

    vector<int> s(n + 5), e(n + 5);
    int time = 0;

    auto dfs = [&](int u, auto &dfs) -> void {
        s[u] = time;
        time++;

        for(int &i : g[u])
            dfs(i, dfs);
        e[u] = time;
        return;
    };
    dfs(1, dfs);

    map<pii, int> mapa;
    auto dfs2 = [&](int u, int r, int v, auto &dfs2) -> int {
        v += (rr[u] == r);

        int v2 = (rr[u] == r); 
        for(int &i : g[u]) 
            v2 += dfs2(i, r, v, dfs2);

        int i = rr[u], j = r;
        mapa[{j, i}] += v;

        int sz = rs[i].size();
        if(sz < 450)
            mapa[{i, j}] += v2;
        
        return v2;
    };

    for(int i = 1; i <= r; i++) {
        int sz = rs[i].size();
        if(sz >= 450) 
            dfs2(1, i, 0, dfs2);
    }

    while(q--) {
        int r1, r2;
        cin >> r1 >> r2;
        
        if(mapa.find({r1, r2}) != mapa.end()) {
            cout << mapa[{r1, r2}] << endl << flush;
            continue;
        }

        for(int &j : rs[r2]) 
            modify(s[j], 1);
        
        int ans = 0;
        for(int &k : rs[r1]) 
            ans += query(s[k], e[k]);

        for(int &j : rs[r2])
            modify(s[j], 0);

        cout << ans << '\n' << flush;

    }
}

int32_t main() {
    FAST;
    int ct = 1;
    // cin >> ct;
    while(ct--)
        solve();
    return 0;
}

Compilation message (stderr)

regions.cpp: In function 'void setIO(std::string)':
regions.cpp:25:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   25 |     freopen((s+".in").c_str(),"r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
regions.cpp:26:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |     freopen((s+".out").c_str(),"w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 35 / 85