Submission #380762

#	Time	Username	Problem	Language	Result	Execution time	Memory
380762		mariowong	Watching (JOI13_watching)	C++14	0 / 100	2 ms	364 KiB

watching

#include <bits/stdc++.h>
using namespace std;

long long l,r,mid,n,p,q,a[2005],dp[2005][2005];
deque <int> dq; 
int main(){
	ios::sync_with_stdio(false);
	cin >> n >> p >> q;
	for (int i=1;i<=n;i++){
		cin >> a[i];
	}
	sort(a+1,a+1+n);
	l=1; r=1e9;
	while (l < r){
		mid=(l+r)/2;
		for (int i=1;i<=min(n,q);i++){ //used how many large
			for (int j=1;j<=n;j++){
				dp[i][j]=0;
			}
		}
		for (int i=0;i<=min(n,q);i++){ //used how many large
			dq.push_back(0);
			for (int j=1;j<=n;j++){
				while (!dq.empty() && a[j]-a[dq.front()+1] > mid) dq.pop_front();
				if (!dq.empty())
				dp[i][j]=dp[i][dq.front()]+1;
				else
				dp[i][j]=1e18;
				while (!dq.empty() && dp[i][j] <= dp[i][dq.back()]) dq.pop_back();
				dq.push_back(j);
			}
			while (!dq.empty()) dq.pop_back();
			if (i > 0){
				dq.push_back(0);
				for (int j=1;j<=n;j++){
					while (!dq.empty() && a[j]-a[dq.front()+1] > 2*mid) dq.pop_front();
					if (dq.empty()){
						l=mid+1;
						while (!dq.empty()) dq.pop_back();
						goto out;
					}
					dp[i][j]=min(dp[i][j],dp[i-1][dq.front()]);
					while (!dq.empty() && dp[i-1][j] <= dp[i-1][dq.back()]) dq.pop_back();
					dq.push_back(j);
				}
				while (!dq.empty()) dq.pop_back();
			}
		}
	/*	cout << l << " " << r << "\n";
		for (int i=1;i<=min(n,q);i++){ //used how many large
			for (int j=1;j<=n;j++){
				cout << dp[i][j] << " ";
			}
			cout << "\n";
		}*/
		if (dp[min(n,q)][n] <= p)
		r=mid;
		else
		l=mid+1;
		out:;
	}
	cout << l << "\n";
	return 0;
}	

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