Submission #30872

#	Time	Username	Problem	Language	Result	Execution time	Memory
30872		Navick	Watching (JOI13_watching)	C++14	100 / 100	263 ms	17968 KiB

watching

#include <bits/stdc++.h>
#define F first
#define S second
#define pii pair<int, int>
#define pb push_back

using namespace std;

typedef long long ll;
typedef long double ld;

const int N = 2010, INF = 1e9 + 10;

int dp[N][N], n, p, q;
int a[N];

bool check(int w){
	for(int j=0; j<=p; j++)
		dp[0][j] = 0;
	int ptr = -1, ptr2 = -1;
	for(int i=1; i<=n; i++){
		while(a[i - 1] - a[ptr + 1] >= w)ptr++;
		while(a[i - 1] - a[ptr2 + 1] >= 2*w)ptr2++;
		for(int j=0; j<=p; j++){
			dp[i][j] = INF;
			if(j > 0)
				dp[i][j] = dp[ptr + 1][j - 1];
			if(q > 0){
				dp[i][j] = min(dp[i][j], dp[ptr2 + 1][j] + 1);
			}
		}
	}
	if(dp[n][p] <= q)return true;
	return false;
}

int main(){
	ios_base::sync_with_stdio(0); cin.tie(0);
	cin >> n >> p >> q;
	p = min(p, n);
	q = min(q, n);

	for(int i=0; i<n; i++)
		cin >> a[i];

	sort(a, a + n);
	n = unique(a,a + n) - a;

	int lo = 0, hi = INF;

	while(hi - lo > 1){
		int mid = (lo + hi)/2;
		if(check(mid))hi = mid;
		else lo = mid;
	}

	cout << hi << endl;
}

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