Submission #1217722

#	Time	Username	Problem	Language	Result	Execution time	Memory
1217722		abczz	Sparklers (JOI17_sparklers)	C++20	0 / 100	1 ms	528 KiB

sparklers

#include <iostream>
#include <vector>
#define ll long long

using namespace std;

vector <ll> A, B;
ll n, k, t, l, r, mid, X[100000];
bool solve(ll u) {
  u *= 2;
  ll j = 0;
  ll xa = 0, xb = 0, tot = 1;
  for (ll i=0; i<A.size(); ++i) {
    while ((i+j+1)*u-xb < A[i]) {
      if (j < B.size() && xa+B[j] <= (i+j+1)*u) {
        xb = B[j];
        ++j;
      }
      else break;
    }
    if ((i+j+1)*u-xb < A[i]) return 0;
    xa = A[i];
  }
  while (j < B.size() && xa+B[j] <= ((ll)A.size()+j+1)*u) {
    ++j;
  }
  if (j == B.size()) return 1;
  else return 0;
}
int main() {
  cin >> n >> k >> t;
  --k;
  for (int i=0; i<n; ++i) cin >> X[i];
  for (int i=k-1; i>=0; --i) A.push_back(X[k]-X[i]);
  for (int i=k+1; i<n; ++i) B.push_back(X[i]-X[k]);
  l = 0, r = ((ll)1e9+t-1)/t;
  while (l < r) {
    mid = (l+r)/2;
    if (solve(mid*t)) r = mid;
    else l = mid+1;
  }
  cout << l << '\n';
}

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