Submission #1006293

#	Time	Username	Problem	Language	Result	Execution time	Memory
1006293		MilosMilutinovic	Discharging (NOI20_discharging)	C++14	100 / 100	321 ms	151232 KiB

Discharging

#include <bits/stdc++.h>

using namespace std;

const int N = 1000100;

const long long inf = (long long) 1e18;

vector<int> xs;

struct Line { 
  long long k;
  long long n;
  Line(long long _k = 0, long long _n = inf) : k(_k), n(_n) {}
  long long val(long long x) {
    return k * x + n;
  }
} seg[8 * N];

void Modify(int id, int l, int r, Line ln) {
  int mid = (l + r) >> 1;
  if (ln.val(xs[mid]) < seg[id].val(xs[mid])) {
    swap(ln, seg[id]);
  }
  if (l == r) {
    return;
  }
  if (ln.val(xs[l]) < seg[id].val(xs[l])) {
    Modify(id * 2, l, mid, ln); 
  } else {
    Modify(id * 2 + 1, mid + 1, r, ln);
  }
}

long long Query(int id, int l, int r, int p) {
  if (l == r) {
    return seg[id].val(xs[p]);
  }
  int mid = (l + r) >> 1;
  if (p <= mid) {
    return min(seg[id].val(xs[p]), Query(id * 2, l, mid, p));
  } else {
    return min(seg[id].val(xs[p]), Query(id * 2 + 1, mid + 1, r, p));
  }
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  cin >> n;
  vector<int> a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i];
  }
  for (int i = 0; i < n; i++) {
    xs.push_back(a[i]);
  }
  sort(xs.begin(), xs.end());
  xs.erase(unique(xs.begin(), xs.end()), xs.end());
  int k = (int) xs.size();
  vector<long long> dp(n, inf);
  int ptr = 0;
  int idx = 0;
  for (int i = 0; i < n; i++) {
    if (a[i] >= a[idx]) {
      idx = i;
    }
    while (ptr <= idx) {
      Modify(1, 0, k - 1, Line(n - ptr, (ptr == 0 ? 0LL : dp[ptr - 1])));
      ptr += 1;
    }
    int p = (int) (lower_bound(xs.begin(), xs.end(), a[idx]) - xs.begin());
    dp[i] = Query(1, 0, k - 1, p);
  }
  cout << dp[n - 1] << '\n';
  return 0;
} 

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 25 / 25
• Subtask 4: 11 / 11
• Subtask 5: 14 / 14
• Subtask 6: 28 / 28