Submission #1097097

#	Time	Username	Problem	Language	Result	Execution time	Memory
1097097		TrinhKhanhDung	Watching (JOI13_watching)	C++14	100 / 100	179 ms	16216 KiB

watching

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18 + 10
#define INF (ll)1e9
#define MOD (ll)(998244353)

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

const int MAX = 2e3 + 10;

int N, P, Q;
int a[MAX], dp[MAX][MAX], small[MAX], large[MAX];

void solve(){
    cin >> N >> P >> Q;
    for(int i = 1; i <= N; i++) cin >> a[i];
    sort(a + 1, a + N + 1);

    minimize(P, N);
    minimize(Q, N);

    auto OK = [&](int range) -> bool{
        int j = N, k = N;
        for(int i = N; i >= 1; i--){
            while(a[j] - a[i] + 1 > range) j--;
            while(a[k] - a[i] + 1 > 2 * range) k--;
            small[i] = j;
            large[i] = k;
        }
        small[N + 1] = large[N + 1] = N;
        for(int i = 0; i <= P; i++){
            memset(dp[i], 0, (Q + 3) * sizeof(int));
        }
        for(int i = 0; i <= P; i++) for(int j = 0; j <= Q; j++){
            if(i < P){
                maximize(dp[i + 1][j], small[dp[i][j] + 1]);
            }
            if(j < Q){
                maximize(dp[i][j + 1], large[dp[i][j] + 1]);
            }
        }
        return dp[P][Q] >= N;
    };

    int l = 1, r = (int)1e9;
    while(l < r){
        int m = (l + r) >> 1;
        if(OK(m)) r = m;
        else l = m + 1;
    }

    cout << r << "\n";
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
//    freopen("task.inp","r",stdin);
//    freopen("task.out","w",stdout);

    int T = 1;
//    cin >> T;
    for(; T; T--) solve();

    return 0;
}

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