oj.uz

Submission #869981

# Submission time Handle Problem Language Result Execution time Memory
869981 2023-11-06T13:18:37 Z green_gold_dog Monochrome Points (JOI20_monochrome) C++17
4 / 100
 28 ms 468 KB 
//#pragma GCC optimize("Ofast")
//#pragma GCC target("avx,avx2,sse,sse2,sse3,ssse3,sse4,abm,popcnt,mmx")
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef double db;
typedef long double ldb;
typedef complex<double> cd;

constexpr ll INF64 = 9'000'000'000'000'000'000, INF32 = 2'000'000'000, MOD = 1'000'000'007;
constexpr db PI = acos(-1);
constexpr bool IS_FILE = false, IS_TEST_CASES = false;

random_device rd;
mt19937 rnd32(rd());
mt19937_64 rnd64(rd());

template<typename T>
bool assign_max(T& a, T b) {
        if (b > a) {
                a = b;
                return true;
        }
        return false;
}

template<typename T>
bool assign_min(T& a, T b) {
        if (b < a) {
                a = b;
                return true;
        }
        return false;
}

template<typename T>
T square(T a) {
        return a * a;
}

template<>
struct std::hash<pair<ll, ll>> {
        ll operator() (pair<ll, ll> p) const {
                return ((__int128)p.first * MOD + p.second) % INF64;
        }
};

set<pair<ll, ll>> bw, rbw, wb, rwb;

void e(ll l, ll r) {
        bw.erase(make_pair(l, r));
        rbw.erase(make_pair(r, l));
        wb.erase(make_pair(l, r));
        rwb.erase(make_pair(r, l));
}

void iwb(ll l, ll r);

void ibw(ll l, ll r) {
        if (r < l) {
                iwb(r, l);
                return;
        }
        auto it = bw.lower_bound(make_pair(l, r));
        if (it != bw.end() && it->second < r) {
                auto[nl, nr] = *it;
                e(nl, nr);
                ibw(l, nr);
                ibw(nl, r);
                return;
        }
        if (it != bw.begin()) {
                it--;
                if (it->second > r) {
                        auto[nl, nr] = *it;
                        e(nl, nr);
                        ibw(l, nr);
                        ibw(nl, r);
                        return;
                }
        }
        it = wb.lower_bound(make_pair(r, 0));
        if (it != wb.end()) {
                auto[nl, nr] = *it;
                e(nl, nr);
                ibw(l, nl);
                iwb(r, nr);
                return;
        }
        it = rwb.lower_bound(make_pair(l, 0));
        if (it != rwb.begin()) {
                it--;
                auto[nr, nl] = *it;
                e(nl, nr);
                ibw(nr, r);
                iwb(nl, l);
                return;
        }
        bw.insert(make_pair(l, r));
        rbw.insert(make_pair(r, l));
}

void iwb(ll l, ll r) {
        if (r < l) {
                ibw(r, l);
                return;
        }
        auto it = wb.lower_bound(make_pair(l, r));
        if (it != wb.end() && it->second < r) {
                auto[nl, nr] = *it;
                e(nl, nr);
                iwb(l, nr);
                iwb(nl, r);
                return;
        }
        if (it != wb.begin()) {
                it--;
                if (it->second > r) {
                        auto[nl, nr] = *it;
                        e(nl, nr);
                        iwb(l, nr);
                        iwb(nl, r);
                        return;
                }
        }
        it = bw.lower_bound(make_pair(r, 0));
        if (it != bw.end()) {
                auto[nl, nr] = *it;
                e(nl, nr);
                iwb(l, nl);
                ibw(r, nr);
                return;
        }
        it = rbw.lower_bound(make_pair(l, 0));
        if (it != rbw.begin()) {
                it--;
                auto[nr, nl] = *it;
                e(nl, nr);
                iwb(nr, r);
                ibw(nl, l);
                return;
        }
        wb.insert(make_pair(l, r));
        rwb.insert(make_pair(r, l));
}

bool trybw(bool b = false) {
        if (bw.size() < 2) {
                return false;
        }
        auto[l1, r1] = *bw.begin();
        auto[r2, l2] = *rbw.rbegin();
        e(l1, r1);
        e(l2, r2);
        if (r1 < l2) {
                ll ml = -1, mr = -1;
                for (auto[nl, nr] : bw) {
                        if (nl > r1 || nr < l2) {
                                ml = nl;
                                mr = nr;
                                break;
                        }
                }
                if (ml != -1) {
                        e(ml, mr);
                        swap(r1, mr);
                        swap(mr, r2);
                        ibw(l1, r1);
                        ibw(l2, r2);
                        ibw(ml, mr);
                        return true;
                }
                if (b) {
                        swap(r1, r2);
                        ibw(l1, r1);
                        ibw(l2, r2);
                        return true;
                }
        }
        ibw(l1, r1);
        ibw(l2, r2);
        return false;
}

bool trywb(bool b = false) {
        if (wb.size() < 2) {
                return false;
        }
        auto[l1, r1] = *wb.begin();
        auto[r2, l2] = *rwb.rbegin();
        e(l1, r1);
        e(l2, r2);
        if (r1 < l2) {
                ll ml = -1, mr = -1;
                for (auto[nl, nr] : wb) {
                        if (nl > r1 || nr < l2) {
                                ml = nl;
                                mr = nr;
                                break;
                        }
                }
                if (ml != -1) {
                        e(ml, mr);
                        swap(r1, mr);
                        swap(mr, r2);
                        iwb(l1, r1);
                        iwb(l2, r2);
                        iwb(ml, mr);
                        return true;
                }
                if (b) {
                        swap(r1, r2);
                        iwb(l1, r1);
                        iwb(l2, r2);
                        return true;
                }
        }
        iwb(l1, r1);
        iwb(l2, r2);
        return false;
}

ll count() {
        vector<pair<ll, ll>> all;
        for (auto i : wb) {
                all.push_back(i);
        }
        for (auto i : bw) {
                all.push_back(i);
        }
        ll ans = 0;
        for (auto[l, r] : all) {
                for (auto[nl, nr] : all) {
                        if ((nr > r) && (nl < r) && (nl > l)) {
                                ans++;
                        }
                }
        }
        return ans;
}

void solve() {
        ll n;
        cin >> n;
        string s;
        cin >> s;
        vector<ll> b, w;
        for (ll i = 0; i < n * 2; i++) {
                if (s[i] == 'B') {
                        b.push_back(i);
                } else {
                        w.push_back(i);
                }
        }
        for (ll i = 0; i < n; i++) {
                ibw(b[i], w[i]);
        }
        ll ans = 0, x = 1;
        bool bb = false;
        while (x || trybw() || trywb()) {
                x = 0;
                assign_max(ans, count());
                if (bb) {
                        trybw(true);
                } else {
                        trywb(true);
                }
                bb = !bb;
                assign_max(ans, count());
        }
        cout << ans << '\n';
}

int main() {
        if (IS_FILE) {
                freopen("", "r", stdin);
                freopen("", "w", stdout);
        }
        ios_base::sync_with_stdio(false);
        cin.tie(0);
        cout.tie(0);
        ll t = 1;
        if (IS_TEST_CASES) {
                cin >> t;
        }
        for (ll i = 0; i < t; i++) {
                solve();
        }
}

Compilation message

monochrome.cpp: In function 'int main()':
monochrome.cpp:278:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  278 |                 freopen("", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~
monochrome.cpp:279:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  279 |                 freopen("", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~

Subtask #1
4.0 / 4.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 0 ms 468 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct

Subtask #2
0.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 0 ms 468 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 18 ms 348 KB Output is correct
15 Correct 12 ms 344 KB Output is correct
16 Correct 28 ms 348 KB Output is correct
17 Correct 22 ms 348 KB Output is correct
18 Incorrect 14 ms 348 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #3
0.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 0 ms 468 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 18 ms 348 KB Output is correct
15 Correct 12 ms 344 KB Output is correct
16 Correct 28 ms 348 KB Output is correct
17 Correct 22 ms 348 KB Output is correct
18 Incorrect 14 ms 348 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #4
0.0 / 65.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 344 KB Output is correct
2 Correct 1 ms 348 KB Output is correct
3 Correct 0 ms 348 KB Output is correct
4 Correct 0 ms 348 KB Output is correct
5 Correct 0 ms 348 KB Output is correct
6 Correct 1 ms 348 KB Output is correct
7 Correct 0 ms 468 KB Output is correct
8 Correct 0 ms 348 KB Output is correct
9 Correct 0 ms 348 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 344 KB Output is correct
12 Correct 0 ms 348 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 18 ms 348 KB Output is correct
15 Correct 12 ms 344 KB Output is correct
16 Correct 28 ms 348 KB Output is correct
17 Correct 22 ms 348 KB Output is correct
18 Incorrect 14 ms 348 KB Output isn't correct
19 Halted 0 ms 0 KB -