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Submission #769300

# Submission time Handle Problem Language Result Execution time Memory
769300 2023-06-29T11:40:01 Z danikoynov Cat Exercise (JOI23_ho_t4) C++14
100 / 100
 513 ms 77932 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)
{
    ///cout << "unite " << v << " " << u << endl;
    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(chain_pos[v] - 1, chain_pos[v]); ///cout << "yep" << endl;
        if (active[order[chain_pos[v] + 1]])
            unite(chain_pos[v] + 1, chain_pos[v]);

        //cout << "Bef " << order[chain_pos[v] - 1] << " " << active[order[chain_pos[v] - 1]] << endl;
        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;
            ///cout << active[order[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;
}
/**
8
5 3 8 7 4 6 1 2
1 2
2 4
2 5
3 6
1 3
3 7
2 8

*/

Compilation message

Main.cpp: In function 'void solve()':
Main.cpp:255:10: warning: variable 'chain' set but not used [-Wunused-but-set-variable]
  255 |     bool chain = true;
      |          ^~~~~

Subtask #1
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7508 KB Output is correct
2 Correct 5 ms 7516 KB Output is correct
3 Correct 4 ms 7452 KB Output is correct
4 Correct 4 ms 7520 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 8 ms 7448 KB Output is correct
7 Correct 5 ms 7384 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 4 ms 7512 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct

Subtask #2
7.0 / 7.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7508 KB Output is correct
2 Correct 5 ms 7516 KB Output is correct
3 Correct 4 ms 7452 KB Output is correct
4 Correct 4 ms 7520 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 8 ms 7448 KB Output is correct
7 Correct 5 ms 7384 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 4 ms 7512 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 4 ms 7640 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7636 KB Output is correct
15 Correct 4 ms 7648 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 4 ms 7508 KB Output is correct
2 Correct 5 ms 7516 KB Output is correct
3 Correct 4 ms 7452 KB Output is correct
4 Correct 4 ms 7520 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 8 ms 7448 KB Output is correct
7 Correct 5 ms 7384 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 4 ms 7512 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 4 ms 7640 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7636 KB Output is correct
15 Correct 4 ms 7648 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 9104 KB Output is correct
19 Correct 8 ms 9208 KB Output is correct
20 Correct 8 ms 9172 KB Output is correct
21 Correct 10 ms 9192 KB Output is correct
22 Correct 8 ms 9172 KB Output is correct
23 Correct 9 ms 9152 KB Output is correct
24 Correct 8 ms 9188 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7508 KB Output is correct
2 Correct 5 ms 7516 KB Output is correct
3 Correct 4 ms 7452 KB Output is correct
4 Correct 4 ms 7520 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 8 ms 7448 KB Output is correct
7 Correct 5 ms 7384 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 4 ms 7512 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 4 ms 7640 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7636 KB Output is correct
15 Correct 4 ms 7648 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 9104 KB Output is correct
19 Correct 8 ms 9208 KB Output is correct
20 Correct 8 ms 9172 KB Output is correct
21 Correct 10 ms 9192 KB Output is correct
22 Correct 8 ms 9172 KB Output is correct
23 Correct 9 ms 9152 KB Output is correct
24 Correct 8 ms 9188 KB Output is correct
25 Correct 4 ms 7516 KB Output is correct
26 Correct 9 ms 8916 KB Output is correct
27 Correct 8 ms 9068 KB Output is correct
28 Correct 9 ms 8916 KB Output is correct
29 Correct 9 ms 9044 KB Output is correct
30 Correct 10 ms 8808 KB Output is correct
31 Correct 10 ms 8836 KB Output is correct
32 Correct 10 ms 8788 KB Output is correct
33 Correct 9 ms 8788 KB Output is correct

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7508 KB Output is correct
2 Correct 5 ms 7516 KB Output is correct
3 Correct 4 ms 7452 KB Output is correct
4 Correct 4 ms 7520 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 8 ms 7448 KB Output is correct
7 Correct 5 ms 7384 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 4 ms 7512 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 4 ms 7640 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7636 KB Output is correct
15 Correct 4 ms 7648 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 9104 KB Output is correct
19 Correct 8 ms 9208 KB Output is correct
20 Correct 8 ms 9172 KB Output is correct
21 Correct 10 ms 9192 KB Output is correct
22 Correct 8 ms 9172 KB Output is correct
23 Correct 9 ms 9152 KB Output is correct
24 Correct 8 ms 9188 KB Output is correct
25 Correct 228 ms 77568 KB Output is correct
26 Correct 233 ms 77804 KB Output is correct
27 Correct 239 ms 77804 KB Output is correct
28 Correct 358 ms 77776 KB Output is correct
29 Correct 353 ms 77896 KB Output is correct
30 Correct 349 ms 77772 KB Output is correct
31 Correct 353 ms 77932 KB Output is correct

Subtask #6
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7508 KB Output is correct
2 Correct 5 ms 7508 KB Output is correct
3 Correct 496 ms 61816 KB Output is correct
4 Correct 513 ms 61792 KB Output is correct
5 Correct 502 ms 61884 KB Output is correct

Subtask #7
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 7508 KB Output is correct
2 Correct 5 ms 7516 KB Output is correct
3 Correct 4 ms 7452 KB Output is correct
4 Correct 4 ms 7520 KB Output is correct
5 Correct 3 ms 7512 KB Output is correct
6 Correct 8 ms 7448 KB Output is correct
7 Correct 5 ms 7384 KB Output is correct
8 Correct 4 ms 7508 KB Output is correct
9 Correct 4 ms 7512 KB Output is correct
10 Correct 4 ms 7508 KB Output is correct
11 Correct 4 ms 7636 KB Output is correct
12 Correct 4 ms 7640 KB Output is correct
13 Correct 4 ms 7636 KB Output is correct
14 Correct 5 ms 7636 KB Output is correct
15 Correct 4 ms 7648 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 9104 KB Output is correct
19 Correct 8 ms 9208 KB Output is correct
20 Correct 8 ms 9172 KB Output is correct
21 Correct 10 ms 9192 KB Output is correct
22 Correct 8 ms 9172 KB Output is correct
23 Correct 9 ms 9152 KB Output is correct
24 Correct 8 ms 9188 KB Output is correct
25 Correct 4 ms 7516 KB Output is correct
26 Correct 9 ms 8916 KB Output is correct
27 Correct 8 ms 9068 KB Output is correct
28 Correct 9 ms 8916 KB Output is correct
29 Correct 9 ms 9044 KB Output is correct
30 Correct 10 ms 8808 KB Output is correct
31 Correct 10 ms 8836 KB Output is correct
32 Correct 10 ms 8788 KB Output is correct
33 Correct 9 ms 8788 KB Output is correct
34 Correct 228 ms 77568 KB Output is correct
35 Correct 233 ms 77804 KB Output is correct
36 Correct 239 ms 77804 KB Output is correct
37 Correct 358 ms 77776 KB Output is correct
38 Correct 353 ms 77896 KB Output is correct
39 Correct 349 ms 77772 KB Output is correct
40 Correct 353 ms 77932 KB Output is correct
41 Correct 4 ms 7508 KB Output is correct
42 Correct 5 ms 7508 KB Output is correct
43 Correct 496 ms 61816 KB Output is correct
44 Correct 513 ms 61792 KB Output is correct
45 Correct 502 ms 61884 KB Output is correct
46 Correct 327 ms 70544 KB Output is correct
47 Correct 335 ms 72820 KB Output is correct
48 Correct 318 ms 74972 KB Output is correct
49 Correct 329 ms 72872 KB Output is correct
50 Correct 493 ms 65832 KB Output is correct
51 Correct 477 ms 65868 KB Output is correct
52 Correct 482 ms 65872 KB Output is correct
53 Correct 497 ms 65928 KB Output is correct