Submission #235282

#	Time	Username	Problem	Language	Result	Execution time	Memory
235282		Knps4422	Sparklers (JOI17_sparklers)	C++14	0 / 100	5 ms	640 KiB

sparklers

//#pns thut contains thragma optimization_level 3
//#pragma GCC optimize("Ofast,no-stack-protector,unroll-loops,fast-math,O3")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include<bits/stdc++.h>
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update>ordset;
*/

#define fr first
#define sc second
#define vec vector
#define pb push_back
#define pii pair<int, int>
#define forn(x,y) for(int x = 1 ; x <= y ; ++x)
#define all(x) (x).begin(),(x).end()
#define fast cin.tie(0);cout.tie(0);cin.sync_with_stdio(0);cout.sync_with_stdio(0);


using namespace std;

typedef long long ll;
typedef unsigned int uint;
typedef complex<int> point;
const int nmax = 1005;
const ll linf = 1e18;
const ll mod = 998244353;
const int inf = INT_MAX;

int n, k;
double t;
double pos[nmax];
double dp[nmax][nmax];

bool check(double x ){
	forn(i,n)
		forn(ii,n)dp[i][ii] = -1;
	dp[k][k] = t;
	for(int len = 0 ; len < n ; len++){
		for(int l = 1; l <= n ; l++){
			int r = l + len;
			if(r < n)
			if( dp[l][r]*x*2 >= (pos[r+1] - pos[r]) ) dp[l][r+1] = max( dp[l][r+1] , dp[l][r] + t - (pos[r+1] - pos[r])/(x*2)); 
			if(l > 1 && r <= n)
			if( dp[l][r]*x*2 >= (pos[l] - pos[l-1]) ) dp[l-1][r] = max( dp[l-1][r] , dp[l][r] + t - (pos[l] - pos[l-1])/(x*2)); 
		}
	}
	return (dp[1][n] >= t);
}

int main(){
	fast;
	cin >> n >> k >> t;
	forn(i,n){
		cin >> pos[i];
	}
	int l = 1 , r = 1e9;
	while ( l < r){
		int mid = (l+r)>>1;
		if(check((double)mid)) r = mid;
		else l = mid+1;
	}
	cout << r << '\n';
	
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 20
• Subtask 3: 0 / 50