Submission #253198

#	Time	Username	Problem	Language	Result	Execution time	Memory
253198		rama_pang	Potatoes and fertilizers (LMIO19_bulves)	C++14	100 / 100	191 ms	15212 KiB

bulves

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

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);

  int N;
  cin >> N;
  vector<long long> sum(N);
  for (int i = 0; i < N; i++) {
    int a, b;
    cin >> a >> b;
    sum[i] = a - b;
    if (i > 0) {
      sum[i] += sum[i - 1];
    }
  }
  // We want sum[] to be non-decreasing
  // An operation: choose i, then sum[i] += 1 or sum[i] -= 1
  // sum[0] cannot be decreased (-1 operation) and must be >= 0
  // sum[N - 1] cannot be increased (+1 operation)
  // This is classic Slope Trick
  long long ans = 0;
  priority_queue<long long> pq;
  pq.emplace(0);
  for (int i = 0; i < N; i++) {
    if (sum[i] < 0) {
      ans += 0 - sum[i];
      sum[i] = 0;
    } else if (sum[i] > sum[N - 1]) {
      ans += sum[i] - sum[N - 1];
      sum[i] = sum[N - 1];
    }
    pq.emplace(sum[i]);
    pq.emplace(sum[i]);
    ans += pq.top() - sum[i];
    pq.pop();
  }

  cout << ans << "\n";
  return 0; 
}

• Subtask 1: 24 / 24
• Subtask 2: 10 / 10
• Subtask 3: 20 / 20
• Subtask 4: 10 / 10
• Subtask 5: 36 / 36