Submission #272948

#	Time	Username	Problem	Language	Result	Execution time	Memory
272948		Haunted_Cpp	Discharging (NOI20_discharging)	C++17	100 / 100	377 ms	21880 KiB

Discharging

/**
 *  author: Haunted_Cpp
**/
 
#include <bits/stdc++.h>
using namespace std;
 
#pragma GCC optimize("Ofast")
#pragma GCC target("fma,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,tune=native")
#pragma GCC optimize("unroll-loops")
 
template<typename T> ostream &operator << (ostream &os, const vector<T> &v) { os << '{'; string sep; for (const auto &x : v) os << sep << x, sep = ", "; return os << '}'; }
template<typename T, size_t size> ostream &operator << (ostream &os, const array<T, size> &arr) { os << '{'; string sep; for (const auto &x : arr) os << sep << x, sep = ", "; return os << '}'; }
template<typename A, typename B> ostream &operator << (ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
 
void debug_out() { cerr << endl; }
template<typename Head, typename... Tail> void debug_out(Head H, Tail... T) { cerr << ' ' << H; debug_out(T...); }
 
#ifdef LOCAL
#define debug(...) cerr << "(" << #__VA_ARGS__ << "):", debug_out(__VA_ARGS__)
#else
#define debug(...) 47
#endif
 
class CHT {
private:
  typedef long long i64;
  struct Node {
    Node *l, *r;
    pair<i64, i64> line;
    Node() {
      l = r = nullptr;
      line = {1e9, 1e9};
    }
  };
  Node *root;
  const int LO, HI;
  long long f(const pair<i64, i64> line, int x) {
    return 1LL * x * line.first + line.second;
  }
  void add_line(pair<i64, i64> line, int l, int r, Node *seg) {
    const int mid = l + (r - l) / 2;
    bool esq = f(seg -> line, l) > f(line, l);
    bool middle = f(seg -> line, mid) > f(line, mid);
    if (middle) {
      swap(line, seg -> line);
    }
    if (l == r) return;
    if (esq == middle) {
      if (!seg -> r) seg -> r = new Node;
      add_line(line, mid + 1, r, seg -> r);
    } else {
      if (!seg -> l) seg -> l = new Node;
      add_line(line, l, mid, seg -> l);
    }
  }
  long long query(int l, int r, int where, Node *seg) {
    if (!seg) return 1e18;
    if (l == r) return f(seg -> line, where);
    const int mid = l + (r - l) / 2;
    if (where > mid) {
      return min(query(mid + 1, r, where, seg -> r), f(seg -> line, where));
    }
    return min(query(l, mid, where, seg -> l), f(seg -> line, where));
  }
public:
  CHT() : LO(0), HI(1e9 + 7) {
    root = new Node;
  }
  void add_line(pair<i64, i64> line) {
    add_line(line, LO, HI, root);
  }
  long long get_best(int where) {
    return query(LO, HI, where, root);
  }
};
 
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0); 
  int n;
  cin >> n;
  vector<int> arr(n + 1);
  for (int i = 1; i <= n; i++) cin >> arr[i];
  CHT seg;
  vector<long long> dp(n + 1);
  seg.add_line({0, 0});
  int mx = 0;
  for (int i = 1; i <= n; i++) {
    mx = max(mx, arr[i]);
    dp[i] = 1LL * mx * n + seg.get_best(mx);
    seg.add_line({1LL * -i, dp[i]});
  }
  cout << dp[n] << '\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