Submission #865798

#	Time	Username	Problem	Language	Result	Execution time	Memory
865798		green_gold_dog	Seesaw (JOI22_seesaw)	C++17	0 / 100	1 ms	512 KiB

seesaw

//#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;
        }
};

void solve() {
        ll n;
        cin >> n;
        vector<ll> arr(n);
        ll sum = 0;
        for (ll i = 0; i < n; i++) {
                cin >> arr[i];
                sum += arr[i];
        }
        vector<tuple<ll, ll, ll>> now(1, make_tuple(sum, 0, n - 1));
        double st = sum / (double)n;
        double mi = st, ma = st;
        vector<pair<double, double>> a;
        for (ll j = 1; j < n; j++) {
                vector<tuple<ll, ll, ll>> nnow;
                for (auto[x, l, r] : now) {
                        nnow.emplace_back(x - arr[l], l + 1, r);
                        nnow.emplace_back(x - arr[r], l, r - 1);
                }
                now.clear();
                sort(nnow.begin(), nnow.end());
                for (ll i = 0; i <= nnow.size(); i++) {
                        if ((i == 0 || get<0>(nnow[i - 1]) / (double)(n - j) <= st) && (i == nnow.size() || get<0>(nnow[i]) / (double)(n - j) >= st)) {
                                if (i > 0) {
                                        now.push_back(nnow[i - 1]);
                                }
                                if (i < nnow.size()) {
                                        now.push_back(nnow[i]);
                                }
                                break;
                        }
                }
                if (now.size() == 1) {
                        assign_min(mi, get<0>(now[0]) / (double)(n - j));
                        assign_max(ma, get<0>(now[0]) / (double)(n - j));
                        continue;
                }
                a.emplace_back(get<0>(now[0]) / (double)(n - j), get<0>(now[1]) / (double)(n - j));
        }
        sort(a.begin(), a.end());
        double ans = ma - min(mi, (a.empty() ? mi : a[0].first));
        for (ll i = 0; i < n; i++) {
                assign_max(ma, a[i].second);
                assign_min(ans, ma - min(mi, (i + 1 < a.size() ? a[i].first : mi)));
        }
        cout << setprecision(20) << 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 (stderr)

seesaw.cpp: In function 'void solve()':
seesaw.cpp:71:34: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::tuple<long long int, long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   71 |                 for (ll i = 0; i <= nnow.size(); i++) {
      |                                ~~^~~~~~~~~~~~~~
seesaw.cpp:72:91: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::tuple<long long int, long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   72 |                         if ((i == 0 || get<0>(nnow[i - 1]) / (double)(n - j) <= st) && (i == nnow.size() || get<0>(nnow[i]) / (double)(n - j) >= st)) {
      |                                                                                         ~~^~~~~~~~~~~~~~
seesaw.cpp:76:39: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::tuple<long long int, long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |                                 if (i < nnow.size()) {
      |                                     ~~^~~~~~~~~~~~~
seesaw.cpp:93:53: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<std::pair<double, double> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   93 |                 assign_min(ans, ma - min(mi, (i + 1 < a.size() ? a[i].first : mi)));
      |                                               ~~~~~~^~~~~~~~~~
seesaw.cpp: In function 'int main()':
seesaw.cpp:100:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  100 |                 freopen("", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~
seesaw.cpp:101:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  101 |                 freopen("", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 1
• Subtask 2: 0 / 33
• Subtask 3: 0 / 33
• Subtask 4: 0 / 33