Submission #970517

#	Time	Username	Problem	Language	Result	Execution time	Memory
970517		Whisper	Watching (JOI13_watching)	C++17	100 / 100	946 ms	600 KiB

watching

#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
using namespace std;
using ll = long long;

//#define int long long
#define FOR(i, a, b) for (int i = a; i <= b; i++)
#define FORD(i, a, b) for (int i = b; i >= a; i --)
#define REP(i, n) for (int i = 0; i < n; ++i)
#define REPD(i, n) for (int i = n - 1; i >= 0; --i)

#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)

constexpr ll LINF = (1ll << 60);
constexpr int INF = (1ll << 30);
constexpr int Mod = 1e9 + 7;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

void setupIO(){
    #define name "Whisper"
    //Phu Trong from Nguyen Tat Thanh High School for gifted student
    srand(time(NULL));
    cin.tie(nullptr)->sync_with_stdio(false); cout.tie(nullptr);
    //freopen(name".inp", "r", stdin);
    //freopen(name".out", "w", stdout);
    cout << fixed << setprecision(10);
}

template <class X, class Y>
    bool minimize(X &x, const Y &y){
        X eps = 1e-9;
        if (x > y + eps) {x = y; return 1;}
        return 0;
    }

template <class X, class Y>
    bool maximize(X &x, const Y &y){
        X eps = 1e-9;
        if (x + eps < y) {x = y; return 1;}
        return 0;
    }
int nArr, nSmall, nBig;
const int MAX = 2e3 + 1;

int a[MAX];
struct MonotonicQueue: deque<pair<int, int>>{
    void push(int x, int i){
        while (!empty() && back().first >= x) pop_back();
        push_back({x, i});
    }
    void pop(int i){
        if(!empty() && front().second == i) pop_front();
    }
    int get_front(){
        return front().first;
    }
    int get_back(){
        return back().first;
    }
};
void Whisper(){
    cin >> nArr >> nSmall >> nBig;
    for (int i = 1; i <= nArr; ++i) cin >> a[i];
    if (nSmall + nBig >= nArr) return void(cout << 1);

    sort(a + 1, a + nArr + 1);


    auto checkSmall = [&](int w){
        vector<vector<int>> dp(2, vector<int>(nArr + 1, INF));
        int ans = INF;
        for (int v = 0; v <= nSmall; ++v){
            MonotonicQueue light, heavy;
            dp[0][0] = 0;
            if(v > 0)
                light.push(dp[1][0], 0);
            heavy.push(dp[0][0], 0);
            for (int i = 1; i <= nArr; ++i){
                if(v > 0)
                    minimize(dp[0][i], dp[1][i - 1]);
                minimize(dp[0][i], dp[0][i - 1] + 1);

                while (!light.empty() && a[i] - a[light.front().second + 1] + 1 > w) light.pop_front();
                while (!heavy.empty() && a[i] - a[heavy.front().second + 1] + 1 > 2 * w) heavy.pop_front();

                if(!light.empty()) minimize(dp[0][i], light.get_front());
                if(!heavy.empty()) minimize(dp[0][i], heavy.get_front() + 1);

                if(v > 0)
                    light.push(dp[1][i], i);
                heavy.push(dp[0][i], i);
            }
            minimize(ans, dp[0][nArr]);
            swap(dp[0], dp[1]);
            for (int i = 1; i <= nArr; ++i) dp[0][i] = INF;
        }
        return (ans <= nBig);
    };
    auto checkBig = [&](int w){
        vector<vector<int>> dp(2, vector<int>(nArr + 1, INF));
        int ans = INF;
        for (int v = 0; v <= nBig; ++v){
            MonotonicQueue light, heavy;
            dp[0][0] = 0;
            if(v > 0)
                heavy.push(dp[1][0], 0);
            light.push(dp[0][0], 0);
            for (int i = 1; i <= nArr; ++i){
                if(v > 0)
                    minimize(dp[0][i], dp[1][i - 1]);
                minimize(dp[0][i], dp[0][i - 1] + 1);

                while (!light.empty() && a[i] - a[light.front().second + 1] + 1 > w) light.pop_front();
                while (!heavy.empty() && a[i] - a[heavy.front().second + 1] + 1 > 2 * w) heavy.pop_front();

                if(!light.empty()) minimize(dp[0][i], light.get_front() + 1);
                if(!heavy.empty()) minimize(dp[0][i], heavy.get_front());

                if(v > 0)
                    heavy.push(dp[1][i], i);
                light.push(dp[0][i], i);
            }
            minimize(ans, dp[0][nArr]);
            swap(dp[0], dp[1]);
            for (int i = 1; i <= nArr; ++i) dp[0][i] = INF;
        }
        return (ans <= nSmall);
    };
    int l = 0, r = *max_element(a + 1, a + nArr + 1) + 1;
    int ans = -1;

    while (r - l > 1){
        int mid = (l + r) >> 1;
        int f = (nBig > nSmall ? checkSmall(mid) : checkBig(mid));
        if(f) r = mid, ans = mid;
        else l = mid;
    }

    cout << ans;
}


signed main(){
    setupIO();
    int Test = 1;
//    cin >> Test;
    for ( int i = 1 ; i <= Test ; i++ ){
        Whisper();
        if (i < Test) cout << '\n';
    }
}

• Subtask 1: 50 / 50
• Subtask 2: 50 / 50