Submission #883188

#	Time	Username	Problem	Language	Result	Execution time	Memory
883188		MilosMilutinovic	Sparklers (JOI17_sparklers)	C++14	0 / 100	0 ms	348 KiB

sparklers

#include <bits/stdc++.h>
 
using namespace std;
 
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n, k, t;
  cin >> n >> k >> t;
  --k;
  vector<int> x(n);
  for (int i = 0; i < n; i++) {
    cin >> x[i];
  }
  auto Check = [&](long long s) {
    auto Valid = [&](int from, int to) {
      long long f = t * 1LL * (to - from);
      if (f <= 5e8) {
        f *= 2;
      }
      if (f <= 1e9) {
        f *= s;
      }
      return f >= (x[to] - x[from]);
    };
    int L = k, R = k;
    while (L > 0 || R < n - 1) {
      if (L == 0) {
        if (Valid(L, R + 1)) {
          R += 1;
          continue;
        } else {
          break;
        }
      }
      if (R == n - 1) {
        if (Valid(L - 1, R)) {
          L -= 1;
          continue;
        } else {
          break;
        }
      }
      if (!Valid(L - 1, R) && !Valid(L, R + 1)) {
        break;
      }
      if (!Valid(L - 1, R)) {
        R += 1;
        continue;
      }
      if (!Valid(L, R + 1)) {
        L -= 1;
        continue;
      }
      if (x[L] - x[L - 1] <= x[R + 1] - x[R]) {
        L -= 1;
      } else {
        R += 1;
      }
    }
    return (L == 0 && R == n - 1);
  };
  long long low = 0, high = 2e9, ans = -1;
  while (low <= high) {
    long long mid = low + high >> 1;
    if (Check(mid)) {
      ans = mid;
      high = mid - 1;
    } else {
      low = mid + 1;
    }
  }
  cout << ans << '\n';
  return 0;
}

Compilation message (stderr)

sparklers.cpp: In function 'int main()':
sparklers.cpp:65:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   65 |     long long mid = low + high >> 1;
      |                     ~~~~^~~~~~

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