Submission #872309

#	Time	Username	Problem	Language	Result	Execution time	Memory
872309		green_gold_dog	Sequence (APIO23_sequence)	C++17	100 / 100	1898 ms	97708 KiB

sequence

#include "sequence.h"

#include <bits/stdc++.h>

using namespace std;

typedef int ll;

const ll INF = 1'000'000'000;

struct segment_tree_min {
        vector<ll> tree, m;
        ll size;
        segment_tree_min(ll n) {
                size = n;
                tree.resize(size * 4, 0);
                m.resize(size * 4, 0);
        }
        ll get(ll l, ll r) {
                return get(1, 0, size, l, r);
        }
        ll get(ll v, ll l, ll r, ll ql, ll qr) {
                if (ql <= l && r <= qr) {
                        return tree[v];
                }
                if (qr <= l || r <= ql) {
                        return INF;
                }
                ll mid = (l + r) / 2;
                return min(get(v * 2, l, mid, ql, qr), get(v * 2 + 1, mid, r, ql, qr)) + m[v];
        }
        void add(ll l, ll r, ll x) {
                add(1, 0, size, l, r, x);
        }
        void add(ll v, ll l, ll r, ll ql, ll qr, ll x) {
                if (ql <= l && r <= qr) {
                        tree[v] += x;
                        m[v] += x;
                        return;
                }
                if (qr <= l || r <= ql) {
                        return;
                }
                ll mid = (l + r) / 2;
                add(v * 2, l, mid, ql, qr, x);
                add(v * 2 + 1, mid, r, ql, qr, x);
                tree[v] = min(tree[v * 2], tree[v * 2 + 1]) + m[v];
        }
};

struct segment_tree_max {
        vector<ll> tree, m;
        ll size;
        segment_tree_max(ll n) {
                size = n;
                tree.resize(size * 4, 0);
                m.resize(size * 4, 0);
        }
        ll get(ll l, ll r) {
                return get(1, 0, size, l, r);
        }
        ll get(ll v, ll l, ll r, ll ql, ll qr) {
                if (ql <= l && r <= qr) {
                        return tree[v];
                }
                if (qr <= l || r <= ql) {
                        return -INF;
                }
                ll mid = (l + r) / 2;
                return max(get(v * 2, l, mid, ql, qr), get(v * 2 + 1, mid, r, ql, qr)) + m[v];
        }
        void add(ll l, ll r, ll x) {
                add(1, 0, size, l, r, x);
        }
        void add(ll v, ll l, ll r, ll ql, ll qr, ll x) {
                if (ql <= l && r <= qr) {
                        tree[v] += x;
                        m[v] += x;
                        return;
                }
                if (qr <= l || r <= ql) {
                        return;
                }
                ll mid = (l + r) / 2;
                add(v * 2, l, mid, ql, qr, x);
                add(v * 2 + 1, mid, r, ql, qr, x);
                tree[v] = max(tree[v * 2], tree[v * 2 + 1]) + m[v];
        }
};

ll sequence(ll n, vector<ll> a) {
        segment_tree_min sti(n), stir(n);
        segment_tree_max sta(n), star(n);
        vector<vector<ll>> all(n);
        for (ll i = 0; i < n; i++) {
                sti.add(i, n, 1);
                sta.add(i, n, 1);
                stir.add(0, i + 1, 1);
                star.add(0, i + 1, 1);
                all[a[i] - 1].push_back(i);
        }
        ll ans = 0, ns = n;
        for (ll i = 0; i < n; i++) {
                for (auto j : all[i]) {
                        sti.add(j, n, -1);
                        sti.add(j, n, -1);
                        //stir.add(0, j + 1, -1);
                        //star.add(0, j + 1, -1);
                        ns--;
                }
                ll lst = 0, sub = all[i].size();
                for (ll j = 0; j < all[i].size(); j++) {
                        ll x = all[i][j];
                        sti.add(x, n, 1);
                        sta.add(x, n, -1);
                        ll mmi = stir.get(lst, all[i][j] + 1) - ns - sub, mma = star.get(lst, all[i][j] + 1) - ns - sub;
                        ll ql = all[i][j], qr = n;
                        ll v = 1, l = 0, r = n;
                        ll msi = 0, msa = 0;
                        while (r - l > 1) {
                                msi += sti.m[v];
                                msa += sta.m[v];
                                ll mid = (l + r) / 2;
                                if (mid < ql) {
                                        l = mid;
                                        v = v * 2 + 1;
                                        continue;
                                }
                                ll mi = sti.tree[v * 2 + 1] + mmi + msi, ma = sta.tree[v * 2 + 1] + mma + msa;
                                if ((mi <= -1 && ma >= -1) || (mi <= 0 && ma >= 0) || (mi <= 1 && ma >= 1)) {
                                        v = v * 2 + 1;
                                        l = mid;
                                } else {
                                        v = v * 2;
                                        r = mid;
                                }
                        }
                        ans = max(ans, (ll)((lower_bound(all[i].begin(), all[i].end(), r) - all[i].begin()) - j));
                        sub--;
                        lst = all[i][j] + 1;
                }
                for (auto j : all[i]) {
                        sti.add(j, n, -1);
                        sta.add(j, n, -1);
                        stir.add(0, j + 1, -2);
                        star.add(0, j + 1, -2);
                        ns--;
                }
        }
        return ans;
}

Compilation message (stderr)

sequence.cpp: In function 'll sequence(ll, std::vector<int>)':
sequence.cpp:112:34: warning: comparison of integer expressions of different signedness: 'll' {aka 'int'} and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  112 |                 for (ll j = 0; j < all[i].size(); j++) {
      |                                ~~^~~~~~~~~~~~~~~
sequence.cpp:117:44: warning: unused variable 'qr' [-Wunused-variable]
  117 |                         ll ql = all[i][j], qr = n;
      |                                            ^~

• Subtask 1: 11 / 11
• Subtask 2: 17 / 17
• Subtask 3: 7 / 7
• Subtask 4: 12 / 12
• Subtask 5: 13 / 13
• Subtask 6: 22 / 22
• Subtask 7: 18 / 18