Submission #305094

#	Time	Username	Problem	Language	Result	Execution time	Memory
305094		Bill_00	Watching (JOI13_watching)	C++14	0 / 100	36 ms	8568 KiB

watching

#include <bits/stdc++.h>
using namespace std;
int a[2001];
int dp[2001][2001];
int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	int n,p,q;
	cin >> n >> p >> q;
	for(int i=1;i<=n;i++){
		cin >> a[i];
	}
	sort(a+1,a+n+1);
	if(p>=n || q>=n || p+q>=n){
		cout << 1;
		return 0;
	}
	int l=1,r=1000000000;
	while(l!=r){
		int flag=0;
		for(int i=1;i<=p;i++){
			dp[0][i]=0;
		}
		for(int i=1;i<=n;i++){
			dp[i][0]=1e9;
		}
		int mid=l+r>>1;
		for(int i=1;i<=n;i++){
			for(int j=1;j<=p;j++){
				int b=a[i]-mid+1;
				int id=lower_bound((a+1),(a+i+1),b)-(a+1);
				b=a[i]-2*mid+1;
				int id1=lower_bound((a+1),(a+i+1),b)-(a+1);
				dp[i][j]=min(dp[id][j-1],dp[id1][j]+1);
				if(dp[i][j]>q){
					flag++;
					break;
				}
			}
			if(flag) break;
		}
		if(flag){
			l=mid+1;
		}
		else r=mid;
	}
	//cout << l << endl;
	int mid=l;
	for(int i=1;i<=p;i++){
		dp[0][i]=0;
	}
	for(int i=1;i<=n;i++){
		dp[i][0]=1e9;
	}
	for(int i=1;i<=n;i++){
		for(int j=1;j<=p;j++){
			int b=a[i]-mid+1;
			int id=lower_bound((a+1),(a+n+1),b)-(a+1);
			b=a[i]-2*mid+1;
			int id1=lower_bound((a+1),(a+n+1),b)-(a+1);
			dp[i][j]=min(dp[id][j-1],dp[id1][j]+1);
			//cout << dp[i][j] << ' ' << i << ' ' << j << endl;
		}
	}
	if(dp[n][p]>q){
		l++;
	}
	cout << l;
}

Compilation message (stderr)

watching.cpp: In function 'int main()':
watching.cpp:28:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   28 |   int mid=l+r>>1;
      |           ~^~

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