Submission #559992

#	Time	Username	Problem	Language	Result	Execution time	Memory
559992		amunduzbaev	Sparklers (JOI17_sparklers)	C++17	50 / 100	173 ms	262144 KiB

sparklers

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

#define ar array
#define int long long

const int inf = 1e9 + 5;

signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	int n, k, t; cin>>n>>k>>t;
	
	vector<int> a(n), d(n);
	for(int i=0;i<n;i++) cin>>a[i], a[i] *= 2;
	for(int i=1;i<n;i++){
		d[i] = a[i] - a[i-1];
	}
	k--;
	
	auto check = [&](int s){
		vector<vector<int>> dp(n, vector<int>(n, -1));
		dp[k][k] = t * s;
		for(int len=0;len<n;len++){
			for(int i=0;i+len<n;i++){
				int j=i+len;
				if(j+1<n){
					int D = d[j+1] / 2;
					if(dp[i][j] >= D){
						dp[i][j+1] = max(dp[i][j+1], dp[i][j] - D + t * s);
					}
				} if(i){
					int D = d[i] / 2;
					if(dp[i][j] >= D){
						dp[i-1][j] = max(dp[i-1][j], dp[i][j] - D + t * s);
					}
				}
			}
		}
		
		return (~dp[0][n-1]);
	};
	
	int l = 0, r = 2 * inf;
	while(l < r){
		int m = (l + r) >> 1;
		if(check(m)) r = m;
		else l = m + 1;
	}
	
	cout<<(l+1) / 2<<"\n";
}

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