Submission #651642

#	Time	Username	Problem	Language	Result	Execution time	Memory
651642		Koful123	Watching (JOI13_watching)	C++17	100 / 100	429 ms	15468 KiB

watching

#include <bits/stdc++.h>
using namespace std;
#define endl "\n"
#define pb push_back
#define ff first
#define ss second
#define mod 1000000007
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

int n;
vector<int> v,a,b;
vector<vector<int>> dp;

int f(int pos,int q,int w){
	if(q < 0) return 2037;
	if(pos >= n) return 0;
	if(dp[pos][q] != 2037) return dp[pos][q];
	dp[pos][q] = min(f(a[pos],q,w) + 1,f(b[pos],q-1,w));
	return dp[pos][q];
}

void solve(){

	int p,q;
	cin >> n >> p >> q;

	v.assign(n,0),a.assign(n,0),b.assign(n,0);
	for(int i=0;i<n;i++){
		cin >> v[i];
	}

	if(p + q >= n){
		cout << 1 << endl;
		return;
	}

	auto check = [&](int m){
		dp.assign(n,vector<int>(q+1,2037));
		for(int i=0;i<n;i++){
			a[i] = lower_bound(all(v), v[i] + m) - v.begin();
			b[i] = lower_bound(all(v), v[i] + 2*m) - v.begin();
		}
		return f(0,q,m) <= p;
	};

	sort(all(v));
	int l = 1,r = 1e9;
	while(l < r){
		int m = (l + r) / 2;
		if(check(m)) r = m;
		else l = m + 1;
	}

	cout << l << endl;
}	

signed main(){

	ios::sync_with_stdio(0);
	cin.tie(0);

	int t = 1;
//	cin >> t;

	while(t--)
		solve();

	return 0;
}

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