Submission #1106888

#	Time	Username	Problem	Language	Result	Execution time	Memory
1106888		Yang8on	Regions (IOI09_regions)	C++17	100 / 100	2628 ms	54436 KiB

regions

#include <bits/stdc++.h>
#define Y8o "REGIONS"
#define maxn (int) 2e5 + 5
#define ll long long
#define pii pair<int, int>
#define gb(i, j) ((i >> j) & 1)
#define all(x) x.begin(), x.end()
#define _left id * 2, l, mid
#define _right id * 2 + 1, mid + 1, r
#define fi(i, a, b) for(int i = a; i <= b; i ++)
#define fid(i, a, b) for(int i = a; i >= b; i --)

//#define f first
//#define s second

using namespace std;

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll GetRandom(ll l, ll r) {
    return uniform_int_distribution<ll> (l, r) (rng);
}
void iof() {
    ios_base::sync_with_stdio(0);
    cin.tie(NULL), cout.tie(NULL);
    if(fopen(Y8o".inp", "r"))
    {
        freopen(Y8o".inp", "r", stdin);
//        freopen(Y8o".out", "w", stdout);
    }
}
void ctime() {
    cerr << "\n" << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << "ms\n";
}

const int can = 450;

int n, m, Q, cnt;
int a[maxn];
int in[maxn], out[maxn], vir[maxn], dem[maxn];
vector<pii> cur, qq[maxn];
vector<int> o[maxn], pos[maxn];
vector<int> ans_dw[maxn], ans_up[maxn];

void pre_dfs(int u = 1) {
    in[u] = ++cnt;
    for(int v : o[u]) pre_dfs(v);
    out[u] = cnt;
    qq[a[u]].push_back({ in[u], out[u] });
}

void dfs(int u, int cl, int d) {
    ans_dw[cl][a[u]] += d;
    d += (dem[u] = (a[u] == cl));
    for(int v : o[u]) {
        dfs(v, cl, d);
        dem[u] += dem[v];
    }
    ans_up[cl][a[u]] += dem[u];
}

void solve() {
    cin >> n >> m >> Q;
    fi(i, 1, n) {
        if(i > 1) {
            int u; cin >> u;
            o[u].push_back(i);
        }
        cin >> a[i], pos[a[i]].push_back(i);
    }

    pre_dfs();

    cnt = 0;
    fi(i, 1, m) {
        if(pos[i].size() > can) {
            ans_up[i].assign(m + 1, 0);
            ans_dw[i].assign(m + 1, 0);
            dfs(1, i, 0);
        }
        sort( all(pos[i]), [&](int x, int y) { return in[x] < in[y]; });
    }

    fi(_, 1, Q) {
        int u, v; cin >> u >> v;
        if(pos[u].size() > can) cout << ans_dw[u][v] << endl;
        else if(pos[v].size() > can) cout << ans_up[v][u] << endl;
        else {
//            cur.clear();
//            fi(i, 0, pos[u].size() - 1) {
//                int node = pos[u][i];
//                cur.push_back({ in[node], +1 }), cur.push_back({ out[node] + 1, -1 });
//            }
//            sort(all(cur));
//
//            int j = 0, op = 0; ll res = 0;
//            fi(i, 0, pos[v].size() - 1) {
//                int node = pos[v][i];
//                while(j < cur.size() && cur[j].first <= in[node]) op += cur[j ++].second;
//                res += op;
//            }
//            cout << res << endl;

            int total=0,j=0;
            vector<pii> cc;
            for(auto [l,r]:qq[u]){
                while(j<(int)pos[v].size() && in[pos[v][j]]<=r) cc.push_back({pos[v][j++],1});
                while((int)cc.size()>=2 && in[cc.end()[-2].first]>=l){
                    int u=cc.back().second;cc.pop_back();
                    cc.back().second+=u;
                }
                if(!cc.empty() && in[cc.back().first]>=l) total+=cc.back().second;
            }
            cout << total << endl;
        }
    }
}


signed main() {
    iof();

    int nTest = 1;
//    cin >> nTest;

    while(nTest --) {
        solve();
    }

//    ctime();
    return 0;
}

Compilation message (stderr)

regions.cpp: In function 'void iof()':
regions.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen(Y8o".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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