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Submission #574164

# Submission time Handle Problem Language Result Execution time Memory
574164 2022-06-08T05:23:42 Z MilosMilutinovic Event Hopping (BOI22_events) C++14
100 / 100
 332 ms 42112 KB 
#include <bits/stdc++.h>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);  
  int n, q;
  cin >> n >> q;
  vector<int> l(n), r(n);
  vector<int> xs;
  for (int i = 0; i < n; i++) {
    cin >> l[i] >> r[i];
    xs.push_back(l[i]);
    xs.push_back(r[i]);
  }
  sort(xs.begin(), xs.end());
  xs.erase(unique(xs.begin(), xs.end()), xs.end());
  for (int i = 0; i < n; i++) {
    l[i] = lower_bound(xs.begin(), xs.end(), l[i]) - xs.begin();
    r[i] = lower_bound(xs.begin(), xs.end(), r[i]) - xs.begin();
  }
  /* if (n <= 1000 && q <= 100) {
    while (q--) {
      int x, y;
      cin >> x >> y;
      --x, --y;
      if (x == y) {
        cout << 0 << '\n';
        continue;
      }      
      int ans = 1;
      int idx = x;
      while (idx != y) {
        if (l[y] <= r[idx] && r[idx] <= r[y]) {
          idx = y;
          break;
        }
        int nxt = idx;
        for (int i = 0; i < n; i++) {
          if (l[i] <= r[idx] && r[idx] <= r[i] && r[i] > r[nxt] && r[i] <= r[y]) {
            nxt = i;
          }
        }
        ans += 1;
        if (nxt == idx) {
          break;  
        }
        idx = nxt;
      }
      if (idx != y) {
        cout << "impossible" << '\n';
        continue;
      }
      cout << ans << '\n';
    }
    return 0;
  } */
  vector<int> order(n);
  iota(order.begin(), order.end(), 0);
  sort(order.begin(), order.end(), [&](int i, int j) {
    if (r[i] != r[j]) {
      return r[i] < r[j];
    } else {
      return l[i] < l[j];
    }
  });
  vector<int> id(n);
  for (int i = 0; i < n; i++) {
    id[order[i]] = i;
  }
  vector<int> xl(n), xr(n);
  for (int i = 0; i < n; i++) {
    xl[i] = l[order[i]];
    xr[i] = r[order[i]];
  }
  swap(l, xl);
  swap(r, xr);        
  const int LOG = 17;               
  vector<vector<pair<int, int>>> who(n, vector<pair<int, int>>(LOG));
  for (int i = 0; i < n; i++) {
    who[i][0] = make_pair(l[i], i);
  }
  for (int j = 1; j < LOG; j++) {
    for (int i = 0; i + (1 << j) <= n; i++) {
      who[i][j] = min(who[i][j - 1], who[i + (1 << (j - 1))][j - 1]);
    }
  }
  vector<int> logs(n + 1);
  for (int i = 2; i <= n; i++) {
    logs[i] = logs[i / 2] + 1;
  }
  auto query = [&](int l, int r) {
    int k = logs[r - l + 1];
    return min(who[l][k], who[r - (1 << k) + 1][k]);
  };
  vector<int> prv(n); 
  /* for (int i = 0; i < n; i++) {
    cout << l[i] << " " << r[i] << '\n';
  }
  cout << '\n'; cout << '\n'; */
  for (int i = 0; i < n; i++) {
    int low = 0, high = i; 
    prv[i] = i;
    while (low <= high) {
      int mid = low + high >> 1;
      if (r[mid] >= l[i]) {
        prv[i] = mid;
        high = mid - 1;
      } else {
        low = mid + 1;
      }
    }
    /* cout << "[" << prv[i] + 1 << " " << i + 1 << "]" << '\n'; */
  }
  vector<vector<int>> jump(n, vector<int>(LOG));
  vector<vector<int>> st(n, vector<int>(LOG));
  function<void(int)> buildSparse = [&](int j) {
    for (int i = 0; i < n; i++) {
      st[i][0] = jump[i][j];
    }
    for (int p = 1; p < LOG; p++) {
      for (int i = 0; i + (1 << p) <= n; i++) {
        st[i][p] = min(st[i][p - 1], st[i + (1 << (p - 1))][p - 1]);
      }
    }
  };
  auto get = [&](int l, int r) {
    int k = logs[r - l + 1];
    return min(st[l][k], st[r - (1 << k) + 1][k]);
  };
  for (int i = 0; i < n; i++) {
    jump[i][0] = prv[i];
  }
  for (int j = 1; j < LOG; j++) {
    for (int i = 0; i < n; i++) {
      jump[i][j] = jump[query(jump[i][j - 1], i).second][j - 1]; // min jump[x][j - 1] for x in range [jump[i][j - 1], i]
    }
  }
  while (q--) {
    int x, y;
    cin >> x >> y;
    --x, --y;
    x = id[x];
    y = id[y];
    if (x == y) {
      cout << 0 << '\n';
      continue;
    }
    if (l[y] <= r[x] && r[x] <= r[y]) {
      cout << 1 << '\n';
      continue;
    }
    if (x > y) {
      cout << "impossible" << '\n';
      continue;
    }
    int ans = 0;
    for (int i = LOG - 1; i >= 0; i--) {
      if (jump[y][i] > x) {
        ans += (1 << i);
        y = query(jump[y][i], y).second;
      }
    }
    if (jump[y][0] > x) {
      cout << "impossible" << '\n';
      continue;
    } else {
      ans += 1;
    }
    cout << ans << '\n';
  }
  return 0;
}

Compilation message

events.cpp: In function 'int main()':
events.cpp:106:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  106 |       int mid = low + high >> 1;
      |                 ~~~~^~~~~~
events.cpp:128:8: warning: variable 'get' set but not used [-Wunused-but-set-variable]
  128 |   auto get = [&](int l, int r) {
      |        ^~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 180 ms 41568 KB Output is correct
3 Correct 209 ms 41580 KB Output is correct
4 Correct 266 ms 41608 KB Output is correct
5 Correct 212 ms 41664 KB Output is correct
6 Correct 226 ms 41656 KB Output is correct
7 Correct 232 ms 41708 KB Output is correct
8 Correct 183 ms 42000 KB Output is correct
9 Correct 200 ms 42080 KB Output is correct
10 Correct 286 ms 41876 KB Output is correct
11 Correct 272 ms 41964 KB Output is correct
12 Correct 151 ms 42112 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 2 ms 724 KB Output is correct
4 Correct 1 ms 724 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 724 KB Output is correct
7 Correct 2 ms 724 KB Output is correct
8 Correct 2 ms 724 KB Output is correct
9 Correct 1 ms 724 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 2 ms 724 KB Output is correct
4 Correct 1 ms 724 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 724 KB Output is correct
7 Correct 2 ms 724 KB Output is correct
8 Correct 2 ms 724 KB Output is correct
9 Correct 1 ms 724 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 724 KB Output is correct
13 Correct 1 ms 724 KB Output is correct
14 Correct 1 ms 724 KB Output is correct
15 Correct 1 ms 724 KB Output is correct
16 Correct 1 ms 724 KB Output is correct
17 Correct 1 ms 724 KB Output is correct
18 Correct 1 ms 724 KB Output is correct
19 Correct 40 ms 2824 KB Output is correct
20 Correct 35 ms 2744 KB Output is correct
21 Correct 54 ms 3016 KB Output is correct
22 Correct 34 ms 3072 KB Output is correct
23 Correct 29 ms 2936 KB Output is correct
24 Correct 27 ms 2944 KB Output is correct
25 Correct 40 ms 2612 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 2 ms 724 KB Output is correct
4 Correct 1 ms 724 KB Output is correct
5 Correct 1 ms 724 KB Output is correct
6 Correct 1 ms 724 KB Output is correct
7 Correct 2 ms 724 KB Output is correct
8 Correct 2 ms 724 KB Output is correct
9 Correct 1 ms 724 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 724 KB Output is correct
13 Correct 2 ms 724 KB Output is correct
14 Correct 1 ms 724 KB Output is correct
15 Correct 2 ms 724 KB Output is correct
16 Correct 1 ms 724 KB Output is correct
17 Correct 2 ms 724 KB Output is correct
18 Correct 1 ms 724 KB Output is correct
19 Correct 149 ms 41008 KB Output is correct
20 Correct 174 ms 40928 KB Output is correct
21 Correct 181 ms 41012 KB Output is correct
22 Correct 192 ms 40932 KB Output is correct
23 Correct 157 ms 41016 KB Output is correct
24 Correct 162 ms 40928 KB Output is correct
25 Correct 101 ms 41012 KB Output is correct

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 179 ms 41548 KB Output is correct
2 Correct 209 ms 41672 KB Output is correct
3 Correct 225 ms 41568 KB Output is correct
4 Correct 193 ms 42080 KB Output is correct
5 Correct 273 ms 41880 KB Output is correct
6 Correct 284 ms 41780 KB Output is correct
7 Correct 292 ms 41656 KB Output is correct
8 Correct 228 ms 41804 KB Output is correct
9 Correct 166 ms 40924 KB Output is correct
10 Correct 207 ms 41340 KB Output is correct
11 Correct 191 ms 41156 KB Output is correct
12 Correct 234 ms 41320 KB Output is correct

Subtask #6
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 180 ms 41568 KB Output is correct
3 Correct 209 ms 41580 KB Output is correct
4 Correct 266 ms 41608 KB Output is correct
5 Correct 212 ms 41664 KB Output is correct
6 Correct 226 ms 41656 KB Output is correct
7 Correct 232 ms 41708 KB Output is correct
8 Correct 183 ms 42000 KB Output is correct
9 Correct 200 ms 42080 KB Output is correct
10 Correct 286 ms 41876 KB Output is correct
11 Correct 272 ms 41964 KB Output is correct
12 Correct 151 ms 42112 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 0 ms 212 KB Output is correct
15 Correct 2 ms 724 KB Output is correct
16 Correct 1 ms 724 KB Output is correct
17 Correct 1 ms 724 KB Output is correct
18 Correct 1 ms 724 KB Output is correct
19 Correct 2 ms 724 KB Output is correct
20 Correct 2 ms 724 KB Output is correct
21 Correct 1 ms 724 KB Output is correct
22 Correct 0 ms 212 KB Output is correct
23 Correct 0 ms 212 KB Output is correct
24 Correct 1 ms 724 KB Output is correct
25 Correct 1 ms 724 KB Output is correct
26 Correct 1 ms 724 KB Output is correct
27 Correct 1 ms 724 KB Output is correct
28 Correct 1 ms 724 KB Output is correct
29 Correct 1 ms 724 KB Output is correct
30 Correct 1 ms 724 KB Output is correct
31 Correct 40 ms 2824 KB Output is correct
32 Correct 35 ms 2744 KB Output is correct
33 Correct 54 ms 3016 KB Output is correct
34 Correct 34 ms 3072 KB Output is correct
35 Correct 29 ms 2936 KB Output is correct
36 Correct 27 ms 2944 KB Output is correct
37 Correct 40 ms 2612 KB Output is correct
38 Correct 1 ms 212 KB Output is correct
39 Correct 0 ms 212 KB Output is correct
40 Correct 1 ms 724 KB Output is correct
41 Correct 2 ms 724 KB Output is correct
42 Correct 1 ms 724 KB Output is correct
43 Correct 2 ms 724 KB Output is correct
44 Correct 1 ms 724 KB Output is correct
45 Correct 2 ms 724 KB Output is correct
46 Correct 1 ms 724 KB Output is correct
47 Correct 149 ms 41008 KB Output is correct
48 Correct 174 ms 40928 KB Output is correct
49 Correct 181 ms 41012 KB Output is correct
50 Correct 192 ms 40932 KB Output is correct
51 Correct 157 ms 41016 KB Output is correct
52 Correct 162 ms 40928 KB Output is correct
53 Correct 101 ms 41012 KB Output is correct
54 Correct 179 ms 41548 KB Output is correct
55 Correct 209 ms 41672 KB Output is correct
56 Correct 225 ms 41568 KB Output is correct
57 Correct 193 ms 42080 KB Output is correct
58 Correct 273 ms 41880 KB Output is correct
59 Correct 284 ms 41780 KB Output is correct
60 Correct 292 ms 41656 KB Output is correct
61 Correct 228 ms 41804 KB Output is correct
62 Correct 166 ms 40924 KB Output is correct
63 Correct 207 ms 41340 KB Output is correct
64 Correct 191 ms 41156 KB Output is correct
65 Correct 234 ms 41320 KB Output is correct
66 Correct 1 ms 212 KB Output is correct
67 Correct 178 ms 41604 KB Output is correct
68 Correct 187 ms 41544 KB Output is correct
69 Correct 216 ms 41544 KB Output is correct
70 Correct 221 ms 41604 KB Output is correct
71 Correct 237 ms 41744 KB Output is correct
72 Correct 242 ms 41660 KB Output is correct
73 Correct 192 ms 42092 KB Output is correct
74 Correct 218 ms 42084 KB Output is correct
75 Correct 258 ms 41960 KB Output is correct
76 Correct 260 ms 41960 KB Output is correct
77 Correct 176 ms 42092 KB Output is correct
78 Correct 1 ms 260 KB Output is correct
79 Correct 2 ms 768 KB Output is correct
80 Correct 2 ms 668 KB Output is correct
81 Correct 2 ms 724 KB Output is correct
82 Correct 2 ms 724 KB Output is correct
83 Correct 2 ms 724 KB Output is correct
84 Correct 1 ms 724 KB Output is correct
85 Correct 1 ms 724 KB Output is correct
86 Correct 36 ms 2760 KB Output is correct
87 Correct 39 ms 2772 KB Output is correct
88 Correct 49 ms 3052 KB Output is correct
89 Correct 32 ms 3148 KB Output is correct
90 Correct 28 ms 2900 KB Output is correct
91 Correct 33 ms 3004 KB Output is correct
92 Correct 31 ms 2600 KB Output is correct
93 Correct 174 ms 40968 KB Output is correct
94 Correct 145 ms 41024 KB Output is correct
95 Correct 169 ms 41076 KB Output is correct
96 Correct 172 ms 41100 KB Output is correct
97 Correct 168 ms 40904 KB Output is correct
98 Correct 150 ms 40936 KB Output is correct
99 Correct 111 ms 41024 KB Output is correct
100 Correct 327 ms 41668 KB Output is correct
101 Correct 292 ms 41696 KB Output is correct
102 Correct 258 ms 41884 KB Output is correct
103 Correct 198 ms 41404 KB Output is correct
104 Correct 201 ms 41160 KB Output is correct
105 Correct 240 ms 41308 KB Output is correct
106 Correct 245 ms 41664 KB Output is correct
107 Correct 332 ms 41800 KB Output is correct
108 Correct 233 ms 41832 KB Output is correct
109 Correct 227 ms 41812 KB Output is correct
110 Correct 202 ms 41644 KB Output is correct
111 Correct 240 ms 41684 KB Output is correct