oj.uz

답안 #218872

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
218872 2020-04-02T23:31:56 Z rama_pang Two Antennas (JOI19_antennas) C++14
100 / 100
 744 ms 36800 KB 
#include <bits/stdc++.h>
using namespace std;

const int INF = 1e9 + 100;

class SegmentTree {
 private:
  int sz;
  vector<int> C; // C[i] = H[i] if i is active, -INF otherwise. We hold maximum C for each node.
  vector<int> D; // D[i] = max(C[i] - H[j]) so far. We hold maximum D for each node.
  vector<int> L; // lazy propagation, we have to update D[k] = max(D[k], C[k] - L) on segment

  void Push(int n) {
    if (L[n] != INF) {
      L[n * 2] = min(L[n * 2], L[n]); // in order to maximize C[k] - L
      L[n * 2 + 1] = min(L[n * 2 + 1], L[n]);

      D[n * 2] = max(D[n * 2], C[n * 2] - L[n]); // lazy propagation
      D[n * 2 + 1] = max(D[n * 2 + 1], C[n * 2 + 1] - L[n]);

      L[n] = INF;
    }
  }

  void Pull(int n) {
    C[n] = max(C[n * 2], C[n * 2 + 1]); // C helps in lazy propagation to update maximum C - L quickly
    D[n] = max(D[n * 2], D[n * 2 + 1]);
  }

  void PointSetUpdate(int n, int tl, int tr, int k, int H) {
    if (tl == tr) return void(C[n] = H);
    Push(n);
    int mid = (tl + tr) / 2;
    if (k <= mid) {
      PointSetUpdate(n * 2, tl, mid, k, H);
    } else {
      PointSetUpdate(n * 2 + 1, mid + 1, tr, k, H);
    }
    Pull(n);
  }

  void RangeUpdate(int n, int tl, int tr, int l, int r, int H) {
    if (tr < l || r < tl || tl > tr || l > r) return;
    if (l <= tl && tr <= r) {
      D[n] = max(D[n], C[n] - H);
      L[n] = min(L[n], H);
      return;
    }
    Push(n);
    int mid = (tl + tr) / 2;
    RangeUpdate(n * 2, tl, mid, l, r, H);
    RangeUpdate(n * 2 + 1, mid + 1, tr, l, r, H);
    Pull(n);
  }

  int RangeMaximumQuery(int n, int tl, int tr, int l, int r) {
    if (tr < l || r < tl || tl > tr || l > r) return -INF;
    if (l <= tl && tr <= r) return D[n];
    Push(n);
    int mid = (tl + tr) / 2;
    return max(RangeMaximumQuery(n * 2, tl, mid, l, r), 
                RangeMaximumQuery(n * 2 + 1, mid + 1, tr, l, r));
  }
  
 public:
  SegmentTree(int n) : sz(n) {
    C.assign(4 * sz, -INF);
    D.assign(4 * sz, -INF);
    L.assign(4 * sz, INF);
  }

  void PointSetUpdate(int k, int H) { // set C[k] = H
    return PointSetUpdate(1, 0, sz - 1, k, H);
  }

  void RangeUpdate(int l, int r, int H) { // for each k, l <= k <= r, D[k] = max(D[k], C[k] - H)
    return RangeUpdate(1, 0, sz - 1, l, r, H);
  }

  int RangeMaximumQuery(int l, int r) { // RMQ on the array D
    return RangeMaximumQuery(1, 0, sz - 1, max(l, 0), r);
  }
};

vector<int> answer;

void Solve(int N, int Q, vector<int> H, vector<int> A, vector<int> B, 
            vector<int> L, vector<int> R) {
  
  int a;
  vector<vector<pair<int, int>>> events(N); // (type, x)
  // type = 1  -> set C[x] = H[x]
  // type = 2 -> set C[x] = -INF
  // type <= 0  -> query (x, current), query id is -type

  for (int i = 0; i < N; i++) {
    int l = i + A[i], r = i + B[i] + 1; // antenna i is active on segment [l, r)
    if (l < N) events[l].emplace_back(1, i);
    if (r < N) events[r].emplace_back(2, i);
  }

  for (int i = 0; i < Q; i++) {
    events[R[i]].emplace_back(-i, L[i]);
  }

  SegmentTree seg(N);

  for (int t = 0; t < N; t++) {
    reverse(begin(events[t]), end(events[t]));

    while (!events[t].empty()) { // updates
      if (events[t].back().first <= 0) break;
      int type = events[t].back().first;
      int x = events[t].back().second;
      events[t].pop_back();

      if (type == 1) {
        seg.PointSetUpdate(x, H[x]);
      } else {
        seg.PointSetUpdate(x, -INF);
      }
    }

    // for k, t - B[t] <= k <= t - A[t], we update D[k] = max(D[k], C[k] - H[t])
    seg.RangeUpdate(t - B[t], t - A[t], H[t]);

    while (!events[t].empty()) { // queries
      int ql = events[t].back().second;
      int qr = t;
      int qi = -events[t].back().first;
      events[t].pop_back();
      answer[qi] = max(answer[qi], seg.RangeMaximumQuery(ql, qr));
    }
  }
}

void Solve() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);

  int N;
  cin >> N;
  
  vector<int> H(N), A(N), B(N);
  for (int i = 0; i < N; i++) {
    cin >> H[i] >> A[i] >> B[i];
  }

  int Q;
  cin >> Q;

  vector<int> L(Q), R(Q);
  for (int i = 0; i < Q; i++) {
    cin >> L[i] >> R[i];
    L[i]--, R[i]--;
  }

  answer.assign(Q, -1);

  auto Reverse = [&]() {
    // reverse the array
    reverse(begin(H), end(H));
    reverse(begin(A), end(A));
    reverse(begin(B), end(B));
    for (int i = 0; i < Q; i++) {
      L[i] = N - 1 - L[i];
      R[i] = N - 1 - R[i];
      swap(L[i], R[i]);
    }
  };

  Solve(N, Q, H, A, B, L, R);
  Reverse();
  Solve(N, Q, H, A, B, L, R);
}

void Write() {
  for (auto &ans : answer) {
    cout << ans << "\n";
  }
}

int main() {
  Solve();
  Write();
  return 0;
}

Compilation message

antennas.cpp: In function 'void Solve(int, int, std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
antennas.cpp:90:7: warning: unused variable 'a' [-Wunused-variable]
   int a;
       ^

Subtask #1
2.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 384 KB Output is correct
4 Correct 5 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 5 ms 256 KB Output is correct
9 Correct 5 ms 384 KB Output is correct
10 Correct 6 ms 384 KB Output is correct
11 Correct 5 ms 384 KB Output is correct
12 Correct 5 ms 384 KB Output is correct
13 Correct 5 ms 384 KB Output is correct
14 Correct 5 ms 384 KB Output is correct
15 Correct 5 ms 384 KB Output is correct
16 Correct 5 ms 384 KB Output is correct
17 Correct 5 ms 384 KB Output is correct
18 Correct 5 ms 384 KB Output is correct
19 Correct 5 ms 384 KB Output is correct
20 Correct 5 ms 384 KB Output is correct
21 Correct 5 ms 384 KB Output is correct
22 Correct 5 ms 384 KB Output is correct
23 Correct 6 ms 384 KB Output is correct
24 Correct 5 ms 384 KB Output is correct

Subtask #2
11.0 / 11.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 384 KB Output is correct
4 Correct 5 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 5 ms 256 KB Output is correct
9 Correct 5 ms 384 KB Output is correct
10 Correct 6 ms 384 KB Output is correct
11 Correct 5 ms 384 KB Output is correct
12 Correct 5 ms 384 KB Output is correct
13 Correct 5 ms 384 KB Output is correct
14 Correct 5 ms 384 KB Output is correct
15 Correct 5 ms 384 KB Output is correct
16 Correct 5 ms 384 KB Output is correct
17 Correct 5 ms 384 KB Output is correct
18 Correct 5 ms 384 KB Output is correct
19 Correct 5 ms 384 KB Output is correct
20 Correct 5 ms 384 KB Output is correct
21 Correct 5 ms 384 KB Output is correct
22 Correct 5 ms 384 KB Output is correct
23 Correct 6 ms 384 KB Output is correct
24 Correct 5 ms 384 KB Output is correct
25 Correct 92 ms 6448 KB Output is correct
26 Correct 18 ms 1160 KB Output is correct
27 Correct 145 ms 8680 KB Output is correct
28 Correct 144 ms 8824 KB Output is correct
29 Correct 99 ms 6592 KB Output is correct
30 Correct 102 ms 6264 KB Output is correct
31 Correct 107 ms 8112 KB Output is correct
32 Correct 140 ms 8824 KB Output is correct
33 Correct 131 ms 8620 KB Output is correct
34 Correct 76 ms 4472 KB Output is correct
35 Correct 137 ms 9112 KB Output is correct
36 Correct 141 ms 8696 KB Output is correct
37 Correct 87 ms 5528 KB Output is correct
38 Correct 137 ms 8700 KB Output is correct
39 Correct 25 ms 1812 KB Output is correct
40 Correct 160 ms 8696 KB Output is correct
41 Correct 104 ms 7056 KB Output is correct
42 Correct 143 ms 8696 KB Output is correct
43 Correct 51 ms 3380 KB Output is correct
44 Correct 136 ms 8696 KB Output is correct
45 Correct 30 ms 2236 KB Output is correct
46 Correct 135 ms 8696 KB Output is correct
47 Correct 41 ms 2760 KB Output is correct
48 Correct 139 ms 8696 KB Output is correct

Subtask #3
22.0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 356 ms 24288 KB Output is correct
2 Correct 395 ms 26872 KB Output is correct
3 Correct 270 ms 19016 KB Output is correct
4 Correct 393 ms 26872 KB Output is correct
5 Correct 170 ms 12736 KB Output is correct
6 Correct 399 ms 26872 KB Output is correct
7 Correct 375 ms 23388 KB Output is correct
8 Correct 387 ms 26872 KB Output is correct
9 Correct 52 ms 4548 KB Output is correct
10 Correct 408 ms 27084 KB Output is correct
11 Correct 219 ms 16888 KB Output is correct
12 Correct 399 ms 27000 KB Output is correct
13 Correct 272 ms 26824 KB Output is correct
14 Correct 253 ms 26500 KB Output is correct
15 Correct 256 ms 25776 KB Output is correct
16 Correct 231 ms 26128 KB Output is correct
17 Correct 302 ms 27016 KB Output is correct
18 Correct 255 ms 26056 KB Output is correct
19 Correct 269 ms 26320 KB Output is correct
20 Correct 261 ms 26348 KB Output is correct
21 Correct 245 ms 26784 KB Output is correct
22 Correct 256 ms 26468 KB Output is correct
23 Correct 269 ms 26488 KB Output is correct
24 Correct 228 ms 25584 KB Output is correct

Subtask #4
65.0 / 65.0

# 결과 실행 시간 메모리 Grader output
1 Correct 5 ms 384 KB Output is correct
2 Correct 5 ms 384 KB Output is correct
3 Correct 5 ms 384 KB Output is correct
4 Correct 5 ms 384 KB Output is correct
5 Correct 5 ms 384 KB Output is correct
6 Correct 5 ms 384 KB Output is correct
7 Correct 5 ms 384 KB Output is correct
8 Correct 5 ms 256 KB Output is correct
9 Correct 5 ms 384 KB Output is correct
10 Correct 6 ms 384 KB Output is correct
11 Correct 5 ms 384 KB Output is correct
12 Correct 5 ms 384 KB Output is correct
13 Correct 5 ms 384 KB Output is correct
14 Correct 5 ms 384 KB Output is correct
15 Correct 5 ms 384 KB Output is correct
16 Correct 5 ms 384 KB Output is correct
17 Correct 5 ms 384 KB Output is correct
18 Correct 5 ms 384 KB Output is correct
19 Correct 5 ms 384 KB Output is correct
20 Correct 5 ms 384 KB Output is correct
21 Correct 5 ms 384 KB Output is correct
22 Correct 5 ms 384 KB Output is correct
23 Correct 6 ms 384 KB Output is correct
24 Correct 5 ms 384 KB Output is correct
25 Correct 92 ms 6448 KB Output is correct
26 Correct 18 ms 1160 KB Output is correct
27 Correct 145 ms 8680 KB Output is correct
28 Correct 144 ms 8824 KB Output is correct
29 Correct 99 ms 6592 KB Output is correct
30 Correct 102 ms 6264 KB Output is correct
31 Correct 107 ms 8112 KB Output is correct
32 Correct 140 ms 8824 KB Output is correct
33 Correct 131 ms 8620 KB Output is correct
34 Correct 76 ms 4472 KB Output is correct
35 Correct 137 ms 9112 KB Output is correct
36 Correct 141 ms 8696 KB Output is correct
37 Correct 87 ms 5528 KB Output is correct
38 Correct 137 ms 8700 KB Output is correct
39 Correct 25 ms 1812 KB Output is correct
40 Correct 160 ms 8696 KB Output is correct
41 Correct 104 ms 7056 KB Output is correct
42 Correct 143 ms 8696 KB Output is correct
43 Correct 51 ms 3380 KB Output is correct
44 Correct 136 ms 8696 KB Output is correct
45 Correct 30 ms 2236 KB Output is correct
46 Correct 135 ms 8696 KB Output is correct
47 Correct 41 ms 2760 KB Output is correct
48 Correct 139 ms 8696 KB Output is correct
49 Correct 356 ms 24288 KB Output is correct
50 Correct 395 ms 26872 KB Output is correct
51 Correct 270 ms 19016 KB Output is correct
52 Correct 393 ms 26872 KB Output is correct
53 Correct 170 ms 12736 KB Output is correct
54 Correct 399 ms 26872 KB Output is correct
55 Correct 375 ms 23388 KB Output is correct
56 Correct 387 ms 26872 KB Output is correct
57 Correct 52 ms 4548 KB Output is correct
58 Correct 408 ms 27084 KB Output is correct
59 Correct 219 ms 16888 KB Output is correct
60 Correct 399 ms 27000 KB Output is correct
61 Correct 272 ms 26824 KB Output is correct
62 Correct 253 ms 26500 KB Output is correct
63 Correct 256 ms 25776 KB Output is correct
64 Correct 231 ms 26128 KB Output is correct
65 Correct 302 ms 27016 KB Output is correct
66 Correct 255 ms 26056 KB Output is correct
67 Correct 269 ms 26320 KB Output is correct
68 Correct 261 ms 26348 KB Output is correct
69 Correct 245 ms 26784 KB Output is correct
70 Correct 256 ms 26468 KB Output is correct
71 Correct 269 ms 26488 KB Output is correct
72 Correct 228 ms 25584 KB Output is correct
73 Correct 599 ms 31260 KB Output is correct
74 Correct 438 ms 27808 KB Output is correct
75 Correct 559 ms 28396 KB Output is correct
76 Correct 717 ms 36412 KB Output is correct
77 Correct 357 ms 19264 KB Output is correct
78 Correct 612 ms 33440 KB Output is correct
79 Correct 647 ms 32796 KB Output is correct
80 Correct 717 ms 36364 KB Output is correct
81 Correct 256 ms 13104 KB Output is correct
82 Correct 566 ms 31676 KB Output is correct
83 Correct 516 ms 26204 KB Output is correct
84 Correct 744 ms 36364 KB Output is correct
85 Correct 453 ms 32764 KB Output is correct
86 Correct 561 ms 36800 KB Output is correct
87 Correct 298 ms 27440 KB Output is correct
88 Correct 532 ms 36036 KB Output is correct
89 Correct 499 ms 34320 KB Output is correct
90 Correct 561 ms 36292 KB Output is correct
91 Correct 377 ms 30012 KB Output is correct
92 Correct 559 ms 36644 KB Output is correct
93 Correct 302 ms 28824 KB Output is correct
94 Correct 548 ms 36544 KB Output is correct
95 Correct 340 ms 29416 KB Output is correct
96 Correct 525 ms 36020 KB Output is correct