Submission #245786

#	Time	Username	Problem	Language	Result	Execution time	Memory
245786		Osama_Alkhodairy	Sparklers (JOI17_sparklers)	C++17	0 / 100	5 ms	384 KiB

sparklers

#include <bits/stdc++.h>
using namespace std;
#define finish(x) return cout << x << endl, 0
#define ll long long

int n, k, T;
vector <int> x;

bool can(int s){
    int l, r;
    l = r = k;
    double t = T;
    auto calc = [&](double d){
        d /= 2;
        return t - d / s;
    };
    while(l > 0 || r < n - 1){
        if(l > 0){
            double new_t = calc(x[l] - x[l - 1]);
            if(new_t >= 0){
                l--;
                t = new_t + T;
                continue;
            }
        }
        if(r < n - 1){
            double new_t = calc(x[r + 1] - x[r]);
            if(new_t >= 0){
                r++;
                t = new_t + T;
                continue;
            }
        }
        return 0;
    }
    return 1;
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> k >> T;
    x.resize(n);
    for(auto &i : x) cin >> i;
    k--;
    if(x.back() - x[0] == 0) finish(0);
    int l = 1, r = 1e9;
    while(l <= r){
        int mid = (l + r) / 2;
        if(can(mid)) r = mid - 1;
        else l = mid + 1;
    }
    cout << l << endl;
}

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