Submission #1251766

#	Time	Username	Problem	Language	Result	Execution time	Memory
1251766		Thunnus	Watching (JOI13_watching)	C++20	100 / 100	580 ms	31848 KiB

watching

#include<bits/stdc++.h>
using namespace std;
using i64 = long long;
#define int i64
#define vi vector<int>
#define vvi vector<vi>
#define vb vector<bool>
#define fi first
#define se second
#define pii pair<int, int>
#define sz(x) (int)(x).size()

inline void solve(){
    int n, p, q;
    cin >> n >> p >> q; // max n kadar p ve q yeterli
    p = min(n, p), q = min(n, q);
    vi a(n);
    for(int &i : a){
        cin >> i;
    }
    sort(a.begin(), a.end());

    auto check = [&](int w) -> bool {
        vvi dp(n + 1, vi(p + 1, INT32_MAX)); // [n, p] -> #q
        dp[0][0] = 0;
        for(int i = 0; i < n; i++){
            int to_p = upper_bound(a.begin(), a.end(), a[i] + w - 1) - a.begin(), to_q = upper_bound(a.begin(), a.end(), a[i] + 2 * w - 1) - a.begin();
            //cout << "i: " << i << " to_p: " << to_p << " to_q: " << to_q << " w: " << w << "\n";
            for(int j = 0; j <= p; j++){
                if(j < p){
                    dp[to_p][j + 1] = min(dp[to_p][j + 1], dp[i][j]);
                }
                dp[to_q][j] = min(dp[to_q][j], dp[i][j] + 1);
            }
        }
        for(int i = 0; i <= p; i++){
			//cout << "p: " << i << " q: " << dp[n][i] << "\n";
            if(dp[n][i] <= q) return true;
        }
        return false;
    };

    auto bs = [&]() -> int {
        int lo = 1, hi = 1e9, ret = lo, mid;
        while(hi >= lo){
            mid = lo + (hi - lo) / 2;
            if(check(mid)){
                hi = mid - 1;
                ret = mid;
            }
            else{
                lo = mid + 1;
            }
        }
        return ret;
    };

    cout << bs() << "\n";
    return;
}

signed main(){
    //ios_base::sync_with_stdio(false); cin.tie(0);
    int t = 1;
    //cin >> t;
    while(t--){
        solve();
    }
    return 0;
}

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