oj.uz

Submission #769280

# Submission time Handle Problem Language Result Execution time Memory
769280 2023-06-29T11:24:25 Z danikoynov Cat Exercise (JOI23_ho_t4) C++14
41 / 100
 367 ms 77940 KB 
#include<bits/stdc++.h>
#define endl '\n'

using namespace std;
typedef long long ll;

void speed()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
}

const int maxn = 2e5 + 10;

int n, a[maxn], used[maxn], pos[maxn];
vector < int > adj[maxn];
ll dp[maxn];
int rec(int val)
{
    if (used[val])
        return dp[val];
    used[val] = 1;
    int left = 0, right = n + 1;
    for (int i = n; i > val; i --)
    {
        if (pos[i] > pos[val])
        {
            right = min(right, pos[i]);
        }
        else
        {
            left = max(left, pos[i]);
        }
    }

    int mx = -1;
    for (int i = pos[val] + 1; i < right; i ++)
    {
        if (a[i] > mx)
        {
            mx = a[i];
            dp[val] = max(dp[val], (ll)(i - pos[val] + rec(a[i])));
        }
    }
    mx = -1;
    for (int i = pos[val] - 1; i > left; i --)
    {
        if (a[i] > mx)
        {
            mx = a[i];
            dp[val] = max(dp[val], (ll)(pos[val] - i + rec(a[i])));
        }
    }
    return dp[val];
}

int dfs(int v, int p, int mx, int dis, int val)
{
    if (mx > val)
        return 0;

    int ans = 0;
    if (a[v] == mx)
        ans = max((ll)ans, dis + dp[v]);

    for (int u : adj[v])
    {
        if (u == p)
            continue;
        ans = max(ans, dfs(u, v, max(mx, a[u]), dis + 1, val));

    }

    return ans;
}

int best[maxn], par[maxn], depth[maxn];
int tin[maxn], tout[maxn], timer, heavy[maxn];
int occ[2 * maxn], sub[maxn];

void trav(int v)
{
    occ[++ timer] = v;
    tin[v] = timer;
    heavy[v] = -1;
    sub[v] = 1;
    for (int u : adj[v])
    {
        if (u == par[v])
            continue;
        depth[u] = depth[v] + 1;
        par[u] = v;
        trav(u);
        sub[v] += sub[u];
        if (heavy[v] == -1 || sub[heavy[u]] > sub[heavy[v]])
            heavy[v] = u;
        occ[++ timer] = v;
    }
    tout[v] = timer;
}

const int maxlog = 20;
int fp[maxlog][2 * maxn], lg[2 * maxn];

void build_sparse_table()
{
    for (int i = 1; i <= timer; i ++)
    {
        lg[i] = lg[i / 2] + 1;
        fp[0][i] = occ[i];
    }

    for (int j = 1; j < lg[timer]; j ++)
        for (int i = 1; i <= timer - (1 << j) + 1; i ++)
        {
            fp[j][i] = fp[j - 1][i + (1 << (j - 1))];
            if (depth[fp[j - 1][i]] < depth[fp[j][i]])
                fp[j][i] = fp[j - 1][i];
        }
}

int lca_query(int v, int u)
{
    int l = tin[v], r = tin[u];
    if (l > r)
        swap(l, r);
    int len = lg[r - l + 1] - 1, lca = fp[len][r - (1 << len) + 1];
    if (depth[fp[len][l]] < depth[lca])
        lca = fp[len][l];
    return lca;
}

int distance(int v, int u)
{
    return depth[v] + depth[u] - 2 * depth[lca_query(v, u)];
}

struct chain
{
    int left, right, head;

    chain()
    {
        left = 0;
        right = 0;
        head = 0;
    }
} chains[maxn];

int chain_count, chain_idx[maxn], chain_pos[maxn];
int order[maxn];
void hld(int v)
{
    chain_idx[v] = chain_count;
    chain_pos[v] = ++ chains[chain_count].right;
    order[chains[chain_count].right] = v;
    if (heavy[v] != -1)
    {
        hld(heavy[v]);
    }
    for (int u : adj[v])
    {
        if (u == par[v] || u == heavy[v])
            continue;
        chain_count ++;
        chains[chain_count].left = chains[chain_count - 1].right + 1;
        chains[chain_count].right = chains[chain_count - 1].right;
        chains[chain_count].head = u;
        hld(u);
    }
}

int tree[4 * maxn], lazy[4 * maxn];

void propagate(int root, int left, int right)
{
    if (lazy[root] == 0)
        return;

    if (left != right)
    {
        tree[root * 2] = lazy[root];
        tree[root * 2 + 1] = lazy[root];
        lazy[root * 2] = lazy[root];
        lazy[root * 2 + 1] = lazy[root];
    }
    lazy[root] = 0;
}

void update(int root, int left, int right, int qleft, int qright, int val)
{
    if (left > qright || right < qleft)
        return;

    if (left >= qleft && right <= qright)
    {
        tree[root] = val;
        lazy[root] = val;
        return;
    }


    propagate(root, left, right);
    int mid = (left + right) / 2;
    update(root * 2, left, mid, qleft, qright, val);
    update(root * 2 + 1, mid + 1, right, qleft, qright, val);
    tree[root] = max(tree[root * 2], tree[root * 2 + 1]);
}

int query(int root, int left, int right, int qleft, int qright)
{
    if (left > qright || right < qleft)
        return 0;
    if (left >= qleft && right <= qright)
        return tree[root];
    propagate(root, left, right);
    int mid = (left + right) / 2;
    return max(query(root * 2, left, mid, qleft, qright),
               query(root * 2 + 1, mid + 1, right, qleft, qright));
}

int lead[maxn], lf_lead[maxn], rf_lead[maxn];

int find_leader(int v)
{
    if (v == lead[v])
        return v;
    return (lead[v] = find_leader(lead[v]));
}

void unite(int v, int u)
{
    v = find_leader(v);
    u = find_leader(u);
    if (v == u)
        return;
    lf_lead[v] = min(lf_lead[v], lf_lead[u]);
    rf_lead[v] = max(rf_lead[v], rf_lead[u]);
    lead[u] = v;
}

int active[maxn];
void solve()
{
    cin >> n;
    for (int i = 1; i <= n; i ++)
    {
        cin >> a[i];
        pos[a[i]] = i;
    }


    bool chain = true;
    for (int i = 1; i < n; i ++)
    {
        int v, u;
        cin >> v >> u;
        if (!(v == i && u == i + 1))
            chain = false;

        adj[v].push_back(u);
        adj[u].push_back(v);
    }




    trav(1);
    build_sparse_table();
    timer = 0;
    chain_count = 1;
    chains[chain_count].left = 1;
    chains[chain_count].right = 0;
    chains[chain_count].head = 1;
    hld(1);
    /**for (int i = 1; i <= chain_count; i ++)
    {
        cout << "chain " << i << endl;
        for (int j = chains[i].left; j <= chains[i].right; j ++)
            cout << order[j] << " ";
        cout << endl;
    }*/

    for (int i = 1; i <= n; i ++)
    {
        lf_lead[i] = rf_lead[i] = lead[i] = i;
    }

    for (int i = 1; i <= n; i ++)
    {

        int v = pos[i];
        active[v] = 1;
        //cout << "step" << endl;
        //cout << v << endl;
        for (int u : adj[v])
        {
            ///cout << u << endl;
            if (u == par[v])
                continue;
            ///cout << "fine" << endl;
            int cur = query(1, 1, n, chain_pos[u], chain_pos[u]);
            ///cout << chain_pos[u] << " : " << chain_pos[u] << endl;
            if (cur != 0)
            {
                ///cout << "check " << cur << endl;
                dp[v] = max(dp[v], dp[pos[cur]] + distance(v, pos[cur]));
            }
        }

        if (active[order[chain_pos[v] - 1]])
            unite(order[chain_pos[v] - 1], v);
        if (active[order[chain_pos[v] + 1]])
            unite(order[chain_pos[v] + 1], v);

        int cur_idx = chain_idx[v], cur_pos = chain_pos[v];
        while(true)
        {
            if (a[order[cur_pos]] > i)
                break;
            int cur_lead = find_leader(cur_pos), lf = chains[cur_idx].left, rf = cur_pos;
            lf = max(lf, lf_lead[cur_lead]);
            int cur_best = query(1, 1, n, lf, rf);
            ///cout << "check " << cur_best << " range " << lf << " " << rf << " " << lf_lead[cur_lead] << endl;
            if (cur_best != 0)
                dp[v] = max(dp[v], dp[pos[cur_best]] + distance(v, pos[cur_best]));

            if (lf_lead[cur_lead] > chains[cur_idx].left || par[chains[cur_idx].head] == 0)
                break;

            cur_pos = chain_pos[par[chains[cur_idx].head]];
            cur_idx = chain_idx[order[cur_pos]];
        }

        cur_idx = chain_idx[v];
        cur_pos = chain_pos[v];

        while(true)
        {
            if (a[order[cur_pos]] > i)
                break;
            int cur_lead = find_leader(cur_pos), lf = chains[cur_idx].left, rf = cur_pos;
            lf = max(lf, lf_lead[cur_lead]);
            update(1, 1, n, lf, rf, i);
            ///cout << "updated " << lf << " " << rf << endl;
            if (lf_lead[cur_lead] > chains[cur_idx].left || par[chains[cur_idx].head] == 0)
                break;

            cur_pos = chain_pos[par[chains[cur_idx].head]];
            cur_idx = chain_idx[order[cur_pos]];
        }
        ///cout << "dp " << v << " " << dp[v] << endl;
    }

    cout << dp[pos[n]] << endl;



}

int main()
{
    speed();
    solve();
    return 0;
}
/**
5
5 3 2 1 4
1 2
2 3
3 4
4 5
*/

Compilation message

Main.cpp: In function 'void solve()':
Main.cpp:254:10: warning: variable 'chain' set but not used [-Wunused-but-set-variable]
  254 |     bool chain = true;
      |          ^~~~~

Subtask #1
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7508 KB Output is correct
2 Correct 4 ms 7508 KB Output is correct
3 Correct 3 ms 7512 KB Output is correct
4 Correct 3 ms 7508 KB Output is correct
5 Correct 4 ms 7512 KB Output is correct
6 Correct 3 ms 7508 KB Output is correct
7 Correct 4 ms 7380 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 3 ms 7508 KB Output is correct
10 Correct 4 ms 7512 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7508 KB Output is correct
2 Correct 4 ms 7508 KB Output is correct
3 Correct 3 ms 7512 KB Output is correct
4 Correct 3 ms 7508 KB Output is correct
5 Correct 4 ms 7512 KB Output is correct
6 Correct 3 ms 7508 KB Output is correct
7 Correct 4 ms 7380 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 3 ms 7508 KB Output is correct
10 Correct 4 ms 7512 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 3 ms 7636 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7640 KB Output is correct
15 Correct 4 ms 7636 KB Output is correct
16 Correct 4 ms 7636 KB Output is correct
17 Correct 4 ms 7636 KB Output is correct

Subtask #3
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7508 KB Output is correct
2 Correct 4 ms 7508 KB Output is correct
3 Correct 3 ms 7512 KB Output is correct
4 Correct 3 ms 7508 KB Output is correct
5 Correct 4 ms 7512 KB Output is correct
6 Correct 3 ms 7508 KB Output is correct
7 Correct 4 ms 7380 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 3 ms 7508 KB Output is correct
10 Correct 4 ms 7512 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 3 ms 7636 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7640 KB Output is correct
15 Correct 4 ms 7636 KB Output is correct
16 Correct 4 ms 7636 KB Output is correct
17 Correct 4 ms 7636 KB Output is correct
18 Correct 8 ms 9188 KB Output is correct
19 Correct 8 ms 9172 KB Output is correct
20 Correct 8 ms 9172 KB Output is correct
21 Correct 9 ms 9172 KB Output is correct
22 Correct 8 ms 9172 KB Output is correct
23 Correct 8 ms 9188 KB Output is correct
24 Correct 8 ms 9172 KB Output is correct

Subtask #4
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7508 KB Output is correct
2 Correct 4 ms 7508 KB Output is correct
3 Correct 3 ms 7512 KB Output is correct
4 Correct 3 ms 7508 KB Output is correct
5 Correct 4 ms 7512 KB Output is correct
6 Correct 3 ms 7508 KB Output is correct
7 Correct 4 ms 7380 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 3 ms 7508 KB Output is correct
10 Correct 4 ms 7512 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 3 ms 7636 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7640 KB Output is correct
15 Correct 4 ms 7636 KB Output is correct
16 Correct 4 ms 7636 KB Output is correct
17 Correct 4 ms 7636 KB Output is correct
18 Correct 8 ms 9188 KB Output is correct
19 Correct 8 ms 9172 KB Output is correct
20 Correct 8 ms 9172 KB Output is correct
21 Correct 9 ms 9172 KB Output is correct
22 Correct 8 ms 9172 KB Output is correct
23 Correct 8 ms 9188 KB Output is correct
24 Correct 8 ms 9172 KB Output is correct
25 Correct 4 ms 7508 KB Output is correct
26 Incorrect 9 ms 8928 KB Output isn't correct
27 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7508 KB Output is correct
2 Correct 4 ms 7508 KB Output is correct
3 Correct 3 ms 7512 KB Output is correct
4 Correct 3 ms 7508 KB Output is correct
5 Correct 4 ms 7512 KB Output is correct
6 Correct 3 ms 7508 KB Output is correct
7 Correct 4 ms 7380 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 3 ms 7508 KB Output is correct
10 Correct 4 ms 7512 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 3 ms 7636 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7640 KB Output is correct
15 Correct 4 ms 7636 KB Output is correct
16 Correct 4 ms 7636 KB Output is correct
17 Correct 4 ms 7636 KB Output is correct
18 Correct 8 ms 9188 KB Output is correct
19 Correct 8 ms 9172 KB Output is correct
20 Correct 8 ms 9172 KB Output is correct
21 Correct 9 ms 9172 KB Output is correct
22 Correct 8 ms 9172 KB Output is correct
23 Correct 8 ms 9188 KB Output is correct
24 Correct 8 ms 9172 KB Output is correct
25 Correct 223 ms 77568 KB Output is correct
26 Correct 227 ms 77740 KB Output is correct
27 Correct 224 ms 77800 KB Output is correct
28 Correct 362 ms 77724 KB Output is correct
29 Correct 367 ms 77768 KB Output is correct
30 Correct 357 ms 77940 KB Output is correct
31 Correct 349 ms 77728 KB Output is correct

Subtask #6
0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7508 KB Output is correct
2 Incorrect 3 ms 7508 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #7
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 7508 KB Output is correct
2 Correct 4 ms 7508 KB Output is correct
3 Correct 3 ms 7512 KB Output is correct
4 Correct 3 ms 7508 KB Output is correct
5 Correct 4 ms 7512 KB Output is correct
6 Correct 3 ms 7508 KB Output is correct
7 Correct 4 ms 7380 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 3 ms 7508 KB Output is correct
10 Correct 4 ms 7512 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 3 ms 7636 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7640 KB Output is correct
15 Correct 4 ms 7636 KB Output is correct
16 Correct 4 ms 7636 KB Output is correct
17 Correct 4 ms 7636 KB Output is correct
18 Correct 8 ms 9188 KB Output is correct
19 Correct 8 ms 9172 KB Output is correct
20 Correct 8 ms 9172 KB Output is correct
21 Correct 9 ms 9172 KB Output is correct
22 Correct 8 ms 9172 KB Output is correct
23 Correct 8 ms 9188 KB Output is correct
24 Correct 8 ms 9172 KB Output is correct
25 Correct 4 ms 7508 KB Output is correct
26 Incorrect 9 ms 8928 KB Output isn't correct
27 Halted 0 ms 0 KB -