Submission #671453

#	Time	Username	Problem	Language	Result	Execution time	Memory
671453		amunduzbaev	Sparklers (JOI17_sparklers)	C++17	0 / 100	0 ms	212 KiB

sparklers

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

#define ar array
typedef long long ll;
#define int ll

const int N = 1e5 + 5;
int x[N];

signed main(){
	ios::sync_with_stdio(0); cin.tie(0);
	
	int n, k, T; cin >> n >> k >> T;
	for(int i=1;i<=n;i++){
		cin >> x[i];
	}
	
	x[n + 1] = x[n];
	
	auto check = [&](int s){
		int t = T * s * 2;
		int l = k, r = k, rem = t;
		while(1 < l || r < n){
			if(r == n || (1 < l && x[l] - x[l-1] <= x[r + 1] - x[r])){
				if(rem < (x[l] - x[l-1])) return false;
				rem -= (x[l] - x[l-1]);
				rem += t; l--;
			} else {
				if(rem < (x[r + 1] - x[r])) return false;
				rem -= (x[r + 1] - x[r]);
				rem += t; r++;
			}
			if(rem > 1e18) rem = 1e18;
		}
		
		return true;
	};
	
	int l = 0, r = 1e9;
	while(l < r){
		int m = (l + r) >> 1;
		if(check(m)) r = m;
		else l = m + 1;
	}
	
	cout<<l<<"\n";
}

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