Submission #1038641

#	Time	Username	Problem	Language	Result	Execution time	Memory
1038641		phong	Triple Jump (JOI19_jumps)	C++17	100 / 100	424 ms	88948 KiB

jumps

#include <bits/stdc++.h>

using namespace std;

typedef array<int, 3> Node; // 0/1/2: c/ab/abc

const int maxn = 1 << 19;
const int INF = 1e9;

int n, q;
int A[maxn];
vector<int> p[maxn];
vector<pair<int, int>> query[maxn];

struct segtree {
  Node T[maxn << 1];

  Node upd(const Node&x, const Node& y) {
    return {max(x[0], y[0]), max(x[1], y[1]), max({x[1] + y[0], x[2], y[2]})};
  }

  void init() {
    for (int i = maxn; i < maxn << 1; ++i) T[i] = {A[i - maxn], -INF, -INF};
    for (int i = maxn - 1; i > 0; --i) T[i] = upd(T[2 * i], T[2 * i + 1]);
  }

  void update(int i, int v) {
    i += maxn;
    T[i][1] = max(T[i][1], v);
    T[i][2] = max(T[i][2], T[i][1]  + T[i][0]);
    for (i >>= 1; i > 0; i >>= 1) {
      T[i] = upd(T[2 * i], T[2 * i + 1]);
    }
  }

  int get(int l, int r) {
    Node L = {-INF, -INF, -INF};
    Node R = L;
    for (l += maxn, r += maxn; l < r; l >>= 1, r >>= 1) {
      if (l & 1) {
        L = upd(L, T[l]);
        l++;
      }
      if (r & 1) {
        r--;
        R = upd(T[r], R);
      }
    }
    return upd(L, R)[2];
  }
} seg;
#define task "code"

int main() {
  ios_base::sync_with_stdio(0); cin.tie(NULL);
//  freopen(task".inp", "r", stdin);
//    freopen(task".ans", "w", stdout);
  cin >> n;

  stack<int> st;
  for (int i = 0; i < n; ++i) {
    cin >> A[i];

    while (!st.empty()) {
      int j = st.top(), k = 2 * i - j;
      if (k < n) p[j].push_back(k);
      if (A[j] <= A[i]) st.pop();
      else break;
    }
    st.push(i);
  }
  seg.init();

  cin >> q;
  vector<int> answer(q, 0);
  for (int i = 0; i < q; ++i) {
    int l, r; cin >> l >> r;
    query[l - 1].emplace_back(r - 1, i);
  }

  for (int i = n - 1; i >= 0; --i) {
    for (int j : p[i]) {
      seg.update(j, A[i] + A[(i + j) / 2]);    }
    for (auto it : query[i]) {
      answer[it.second] = seg.get(i, it.first + 1);
    }
  }
  for (int i = 0; i < q; ++i) cout << answer[i] << "\n";
  return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 14 / 14
• Subtask 3: 27 / 27
• Subtask 4: 54 / 54