Submission #1139954

#	Time	Username	Problem	Language	Result	Execution time	Memory
1139954		jackofall718	Watching (JOI13_watching)	C++20	0 / 100	0 ms	328 KiB

watching

#include <bits/stdc++.h>
#include <chrono>
#define ll long long int
#define endl '\n'
#define vn vector<ll>
#define vi vector<pair <ll,ll>>

using namespace std;
using namespace std::chrono;
const int MAX_N = 1e9 + 7;
#define pii pair<ll,ll>
const ll INF = 0x3f3f3f3f3f3f3f3f;

#define pb push_back  
#define srt(vp) sort(vp.begin(), vp.end()) 

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    auto start = high_resolution_clock::now();
    ll n,p,q;
    cin >> n >> p >> q;
    vn v(n);
    for (auto &x : v) cin >> x;
    sort(v.begin(), v.end());
    ll lo = 1;
    ll ho = v[n-1]-v[0];
    while (lo < ho){ 
        ll mid = (lo + ho) / 2;
        ll dp[p+1][q+1] = {}; // be sure to make it empty
        bool check = false;
        for (ll i = 0; i <= p; i++){
            for (ll j = 0; j <= q; j++){
                ll x = i > 0 ? dp[i-1][j] : -1; 
                ll y = j > 0 ? dp[i][j-1] : -1; 
                if (x < n-1 && i > 0){ 
                    ll newdist = upper_bound(v.begin(), v.end(), v[x] + mid) - v.begin() - 1;//i forgot to substract v.begin() so the dp values are the max index they take
                    dp[i][j] = max(dp[i][j], newdist);
                }
                if (y < n-1 && j > 0){ 
                    ll newdist1 = upper_bound(v.begin(), v.end(), v[y] + 2 * mid) - v.begin() - 1; 
                    dp[i][j] = max(dp[i][j], newdist1);
                }
                //basically just dp to decide the optimal placement of small and large shields
                if (dp[i][j] >= n-1){ 
                    check = true;
                }
            }
        }
        if (check) ho = mid; 
        else lo = mid + 1; //mid +1 not mid
    }
    cout<<lo<< endl; 

    auto stop = high_resolution_clock::now();
    auto duration = duration_cast<microseconds>(stop - start);
    //cout << "Time taken by function: " << duration.count() << " microseconds" << endl; // Un-commented for utility

    
    return 0;
}

• Subtask 1: 0 / 50
• Subtask 2: 0 / 50