Submission #107043

#	Time	Username	Problem	Language	Result	Execution time	Memory
107043		Diuven	Watching (JOI13_watching)	C++14	100 / 100	213 ms	16248 KiB

watching

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

typedef long long lint;
int n, p, q, A[2010];

int f(int x){
	if(x<1) return 0;
	// A에서 x이하인 최대 인덱스. 없으면 0
	int pos = upper_bound(A+1, A+n+1, x) - A - 1;
	return pos;
}

inline int _min(int x, int y){ return x<y ? x : y; }

bool check(lint x){
	static int D[2010][2010], E[2010], F[2010];
	for(int i=1; i<=n; i++){
		E[i] = f(A[i] - x);
		F[i] = f(A[i] - 2*x);
	}
	for(int i=1; i<=n; i++) D[0][i] = 0;
	for(int i=1; i<=n; i++){
		int s = E[i], l = F[i];
		D[i][0] = D[l][0] + 1;
		for(int j=1; j<=n; j++)
			D[i][j] = _min(D[s][j-1], D[l][j]+1);
	}
	// cout<<"SOLVE: "<<x<<'\n';
	// for(int i=1; i<=n; i++, cout<<'\n') for(int j=1; j<=n; j++) cout<<D[i][j]<<' ';
	for(int i=0; i<=p; i++)
		if(D[n][i]<=q) return true;
	return false;
}

int main(){
	ios::sync_with_stdio(0); cin.tie(0);

	cin>>n>>p>>q;
	for(int i=1; i<=n; i++) cin>>A[i];
	sort(A+1, A+n+1);

	int s = 1, e = 1e9;

	while(s<e){
		int mid = (s+e)/2;
		if(check(mid)) e = mid;
		else s = mid+1;
	}
	cout<<s<<'\n';
	
	/*
		D[i][j] : 1~i까지, j개 작은 카메라 썼을 때 큰 카메라 최소 수
		D[i][j] = min(D[k][j-1], D[l][j]+1);
	*/

	return 0;
}

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