Submission #894006

#	Time	Username	Problem	Language	Result	Execution time	Memory
894006		azosi	Min-max tree (BOI18_minmaxtree)	C++17	29 / 100	184 ms	30492 KiB

minmaxtree

#include <bits/stdc++.h>

using namespace std;
const int MAX_N = 70070;
const int INF = 1e9 + 100;
int n, q;

struct SegmentTree {
    typedef int (*F)(int, int);

    F merge;
    int identity;
    int tree[MAX_N * 4]{}, lazy[MAX_N * 4]{};

    SegmentTree(F func, int identity) : merge(func), identity(identity) {
        for (int i = 0; i < MAX_N * 4; ++i) tree[i] = lazy[i] = identity;
    }

    void push(int node, int l, int r) {
        if (lazy[node] != identity) {
            tree[node] = merge(tree[node], lazy[node]);
            if (l != r) {
                lazy[node * 2] = merge(lazy[node * 2], lazy[node]);
                lazy[node * 2 + 1] = merge(lazy[node * 2 + 1], lazy[node]);
            }
        }
        lazy[node] = identity;
    }

    void update(int s, int e, int val, int node = 1, int l = 1, int r = MAX_N) {
        push(node, l, r);
        if (e < l || r < s) return;
        if (s <= l && r <= e) {
            lazy[node] = val;
            push(node, l, r);
            return;
        }
        int mid = (l + r) / 2;
        update(s, e, val, node * 2, l, mid);
        update(s, e, val, node * 2 + 1, mid + 1, r);
        tree[node] = merge(tree[node * 2], tree[node * 2 + 1]);
    }

    int query(int s, int e, int node = 1, int l = 1, int r = MAX_N) {
        push(node, l, r);
        if (e < l || r < s) return identity;
        if (s <= l && r <= e) return tree[node];
        int mid = (l + r) / 2;
        return merge(query(s, e, node * 2, l, mid), query(s, e, node * 2 + 1, mid + 1, r));
    }

};

int _mn(int a, int b) {
    return min(a, b);
}

int _mx(int a, int b) {
    return max(a, b);
}

SegmentTree minSeg(_mn, INF), maxSeg(_mx, -INF);
int in[MAX_N], dep[MAX_N], par[MAX_N], top[MAX_N], sz[MAX_N], chk[MAX_N];
int pv;
vector<int> g[MAX_N], inp[MAX_N];

void dfs(int v = 1) {
    chk[v] = 1;
    for (auto i: inp[v]) {
        if (chk[i]) continue;
        chk[i] = 1;
        g[v].push_back(i);
        dfs(i);
    }
}

void dfs1(int v = 1) {
    sz[v] = 1;
    for (auto &i: g[v]) {
        dep[i] = dep[v] + 1;
        par[i] = v;
        dfs1(i);
        sz[v] += sz[i];
        if (sz[i] > sz[g[v][0]]) swap(i, g[v][0]);
    }
}

void dfs2(int v = 1) {
    in[v] = ++pv;
    for (auto i: g[v]) {
        top[i] = i == g[v][0] ? top[v] : i;
        dfs2(i);
    }
}

void update(int a, int b, int op, int k) {
    while (top[a] != top[b]) {
        if (dep[top[a]] < dep[top[b]]) swap(a, b);
        int st = top[a];
        if (op == 1) minSeg.update(in[st], in[a], k);
        else maxSeg.update(in[st], in[a], k);
        a = par[st];
    }
    if (dep[a] > dep[b]) swap(a, b);
    if (op == 1) minSeg.update(in[a] + 1, in[b], k);
    else maxSeg.update(in[a] + 1, in[b], k);
}

int maxi[MAX_N], mini[MAX_N], cnt[MAX_N], ans[MAX_N], vis[MAX_N];

struct Query {
    int s, e, x, mx;
};
vector<Query> qry;
map<int, int> mp;
vector<int> bench[MAX_N];

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    cin >> n;
    top[1] = 1;
    for (int i = 2; i <= n; i++) {
        int s, e;
        cin >> s >> e;
        inp[s].push_back(e);
        inp[e].push_back(s);
    }
    dfs();
    dfs1();
    dfs2();

    cin >> q;

    for (int i = 0; i < q; i++) {
        char op;
        int a, b, c;
        cin >> op >> a >> b >> c;
        if (op == 'm') update(a, b, 2, c);
        else update(a, b, 1, c);
        qry.push_back({a, b, c, op == 'M'});
    }

    for (int i = 0; i < q; i++) {
        mp[qry[i].x] = i;
    }

    for (int i = 2; i <= n; i++) {
        int mx = maxSeg.query(in[i], in[i]);
        int mn = minSeg.query(in[i], in[i]);
        if (mx != -INF) {
            maxi[i] = mp[mx];
            bench[maxi[i]].push_back(i);
        } else maxi[i] = -1;

        if (mn != INF) {
            mini[i] = mp[mn];
            bench[mini[i]].push_back(i);
        } else mini[i] = -1;
    }

    memset(chk, 0, sizeof chk);
    priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> pq;
    for (int i = 0; i < q; i++) {
        cnt[i] = bench[i].size();
        pq.push({bench[i].size(), i});
    }
    while (!pq.empty()) {
        auto [x, y] = pq.top();
        pq.pop();
        if (x != cnt[y]) continue;
        vis[y] = true;
        for (int i: bench[y]) {
            if (chk[i]) continue;
            ans[i] = qry[y].x;
            chk[i] = true;
            if (qry[y].mx) {
                if (maxi[i] != -INF) {
                    cnt[mp[maxi[i]]]--;
                    if (!vis[mp[maxi[i]]]) pq.push({cnt[mp[maxi[i]]], mp[maxi[i]]});
                }
            } else {
                if (mini[i] != INF) {
                    cnt[mp[mini[i]]]--;
                    if (!vis[mp[mini[i]]]) pq.push({cnt[mp[mini[i]]], mp[mini[i]]});
                }
            }
            break;
        }
    }
    for (int i = 2; i <= n; i++) {
        if (!chk[i]) ans[i] = maxi[i];
    }
    for (int i = 2; i <= n; i++) {
        cout << par[i] << " " << i << " " << ans[i] << "\n";
    }
}

• Subtask 1: 7 / 7
• Subtask 2: 22 / 22
• Subtask 3: 0 / 29
• Subtask 4: 0 / 42