Submission #1157403

#	Time	Username	Problem	Language	Result	Execution time	Memory
1157403		zhasyn	Watching (JOI13_watching)	C++20	100 / 100	135 ms	16896 KiB

watching

#include <bits/stdc++.h>
#define pb push_back
#define pf push_front
using namespace std;
#define F first
#define S second
typedef long long ll;
#define pii pair <int, int>
#define pll pair <ll, ll>
typedef long double ld;
const ll N = 2000 + 100, M = 4096 + 10, len = 21, inf = 1e18;
const ll mod = 1e9 + 7;
ll um(ll a, ll b){
	return (1LL * a * b) % mod;
}
ll subr(ll a, ll b){
	return ((1LL * a - b) % mod + mod) % mod;
}
int pos[N], n, a, b, cur[N][N];
bool calc(int x){
	cur[0][a] = b;
	//cout << x << endl;
	for(int i = 0; i < n; i++){
		int lx = n, lxx = n;
		for(int j = i; j < n; j++){
			if(pos[j] > pos[i] + x - 1) lx = min(j, lx);
			if(pos[j] > pos[i] + 2 * x - 1){
				lxx = j;
				break;
			}
		}
		//cout << i << " "<< lx << " " << lxx << endl;
		for(int j = 0; j <= a; j++){
			if(cur[i][j] > 1) cur[lxx][j] = max(cur[lxx][j], cur[i][j] - 1);
			if(j > 0) cur[lx][j - 1] = max(cur[lx][j - 1], cur[i][j]);
		}
		for(int j = 0; j <= a; j++){
			cur[i][j] = 0;
		}
	}
	bool can = false;
	for(int i = 0; i <= a; i++){
		if(cur[n][i] >= 1) can = true;
		cur[n][i] = 0;
	}
	return can;
}
int main(){
  	ios::sync_with_stdio(false);
  	cin.tie(NULL);
  	cin >> n >> a >> b;
  	b++;
  	if(a + b - 1 >= n){
  		cout << 1;
  		return 0;
  	}
  	for(int i = 0; i < n; i++){
  		cin >> pos[i];
  	}
  	sort(pos, pos + n);
  	int l = 0, r = 1e9;
  	while(r - l > 1){
  		int mid = (r + l) / 2;
  		if(calc(mid)) r = mid;
  		else l = mid;
  	}
  	cout << r;
  return 0;
}

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