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Submission #1015845

# Submission time Handle Problem Language Result Execution time Memory
1015845 2024-07-06T22:10:00 Z asdfgrace Event Hopping (BOI22_events) C++17
100 / 100
 86 ms 31420 KB 
#include <bits/stdc++.h>
using namespace std;

#define dbg(x) x
#define prt(x) dbg(cerr << x)
#define pv(x) dbg(cerr << #x << " = " << x << '\n')
#define pv2(x) dbg(cerr << #x << " = " << x.first << ',' << x.second << '\n')
#define parr(x) dbg(prt(#x << " = { "); for (auto y : x) prt(y << ' '); prt("}\n");)
#define parr2(x) dbg(prt(#x << " = { "); for (auto [y, z] : x) prt(y << ',' << z << "  "); prt("}\n");)
#define parr2d(x) dbg(prt(#x << ":\n"); for (auto arr : x) {parr(arr);} prt('\n'));
#define parr2d2(x) dbg(prt(#x << ":\n"); for (auto arr : x) {parr2(arr);} prt('\n'));

/*
sort by right bound
out of everything with l[i] <= r[j] <= r[i]
with leftmost left bound
*/

int main() {
  ios::sync_with_stdio(0); cin.tie(0);
  int n, q;
  cin >> n >> q;
  vector<array<int, 2>> a(n);
  for (int i = 0; i < n; i++) {
    cin >> a[i][0] >> a[i][1];
  }
  vector<int> ord(n);
  iota(ord.begin(), ord.end(), 0);
  sort(ord.begin(), ord.end(), [&] (int x, int y) {
    return a[x][1] < a[y][1] || (a[x][1] == a[y][1] && a[x][0] < a[y][0]);
  });
  vector<int> at(n);
  for (int i = 0; i < n; i++) {
    at[ord[i]] = i;
  }
  sort(a.begin(), a.end(), [&] (array<int, 2> a1, array<int, 2> a2) {
    return a1[1] < a2[1] || (a1[1] == a2[1] && a1[0] < a2[0]);
  });
  vector<int> l(n), r(n);
  for (int i = 0; i < n; i++) {
    l[i] = a[i][0];
    r[i] = a[i][1];
  }
  vector<vector<array<int, 2>>> rmq(20, vector<array<int, 2>>(n));
  for (int i = 0; i < n; i++) {
    rmq[0][i] = {l[i], i};
  }
  for (int j = 1; j < 20; j++) {
    for (int i = 0; i < n - (1 << (j - 1)); i++) {
      rmq[j][i] = min(rmq[j - 1][i], rmq[j - 1][i + (1 << (j - 1))]);
    }
  }
  function<array<int, 2>(int, int)> mnq = [&] (int lb, int rb) {
    int len = rb - lb + 1, mxbit = 31 - __builtin_clz(len);
    return min(rmq[mxbit][lb], rmq[mxbit][rb - (1 << mxbit) + 1]);
  };
  vector<int> to(n);
  for (int i = 0; i < n; i++) {
    int lb = lower_bound(r.begin(), r.end(), l[i]) - r.begin();
    int rb = upper_bound(r.begin(), r.end(), r[i]) - r.begin() - 1;
    array<int, 2> best = mnq(lb, rb);
    to[i] = best[1];
  }
  vector<vector<int>> lift(20, vector<int>(n, 0));
  lift[0] = to;
  for (int j = 1; j < 20; j++) {
    for (int i = 0; i < n; i++) {
      lift[j][i] = lift[j - 1][lift[j - 1][i]];
    }
  }
  while (q--) {
    int st, en;
    cin >> st >> en;
    st--; en--;
    st = at[st]; en = at[en];
    if (r[en] < r[st]) {
      cout << "impossible\n";
      continue;
    } else if (st == en) {
      cout << 0 << '\n';
      continue;
    } else if (l[en] <= r[st]) {
      cout << 1 << '\n';
      continue;
    }
    int ans = 0;
    for (int bit = 19; bit >= 0; bit--) {
      if (l[lift[bit][en]] > r[st]) {
        ans += 1 << bit;
        en = lift[bit][en];
      }
    }
    en = to[en];
    ans++;
    if (l[en] > r[st]) {
      cout << "impossible\n";
    } else {
      cout << ans + 1 << '\n';
    }
  }
}

/*
any observations help

check every line
IF YOUR LINES AREN'T WRONG
CHECK IF YOUR LINES ARE IN THE RIGHT ORDER

NEVER GIVE UP
*/

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 68 ms 27688 KB Output is correct
3 Correct 67 ms 27712 KB Output is correct
4 Correct 73 ms 27712 KB Output is correct
5 Correct 80 ms 27712 KB Output is correct
6 Correct 70 ms 27608 KB Output is correct
7 Correct 70 ms 27712 KB Output is correct
8 Correct 65 ms 28228 KB Output is correct
9 Correct 60 ms 31296 KB Output is correct
10 Correct 81 ms 31420 KB Output is correct
11 Correct 83 ms 31176 KB Output is correct
12 Correct 54 ms 30560 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Correct 0 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 1 ms 604 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Correct 0 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 0 ms 456 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 604 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 1 ms 604 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 1 ms 604 KB Output is correct
17 Correct 1 ms 604 KB Output is correct
18 Correct 1 ms 604 KB Output is correct
19 Correct 23 ms 3264 KB Output is correct
20 Correct 19 ms 3160 KB Output is correct
21 Correct 24 ms 3416 KB Output is correct
22 Correct 23 ms 3420 KB Output is correct
23 Correct 17 ms 3420 KB Output is correct
24 Correct 16 ms 3412 KB Output is correct
25 Correct 18 ms 2908 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 1 ms 604 KB Output is correct
4 Correct 1 ms 604 KB Output is correct
5 Correct 0 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 1 ms 604 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 0 ms 348 KB Output is correct
11 Correct 0 ms 348 KB Output is correct
12 Correct 1 ms 604 KB Output is correct
13 Correct 1 ms 604 KB Output is correct
14 Correct 1 ms 604 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 1 ms 604 KB Output is correct
17 Correct 1 ms 600 KB Output is correct
18 Correct 1 ms 604 KB Output is correct
19 Correct 50 ms 28984 KB Output is correct
20 Correct 47 ms 28228 KB Output is correct
21 Correct 54 ms 28740 KB Output is correct
22 Correct 53 ms 28988 KB Output is correct
23 Correct 52 ms 28872 KB Output is correct
24 Correct 49 ms 28992 KB Output is correct
25 Correct 33 ms 28356 KB Output is correct

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 59 ms 27736 KB Output is correct
2 Correct 66 ms 27608 KB Output is correct
3 Correct 66 ms 27608 KB Output is correct
4 Correct 63 ms 28224 KB Output is correct
5 Correct 70 ms 27888 KB Output is correct
6 Correct 82 ms 27716 KB Output is correct
7 Correct 78 ms 27620 KB Output is correct
8 Correct 76 ms 27948 KB Output is correct
9 Correct 41 ms 26956 KB Output is correct
10 Correct 63 ms 27412 KB Output is correct
11 Correct 69 ms 27200 KB Output is correct
12 Correct 66 ms 27340 KB Output is correct

Subtask #6
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 68 ms 27688 KB Output is correct
3 Correct 67 ms 27712 KB Output is correct
4 Correct 73 ms 27712 KB Output is correct
5 Correct 80 ms 27712 KB Output is correct
6 Correct 70 ms 27608 KB Output is correct
7 Correct 70 ms 27712 KB Output is correct
8 Correct 65 ms 28228 KB Output is correct
9 Correct 60 ms 31296 KB Output is correct
10 Correct 81 ms 31420 KB Output is correct
11 Correct 83 ms 31176 KB Output is correct
12 Correct 54 ms 30560 KB Output is correct
13 Correct 0 ms 348 KB Output is correct
14 Correct 0 ms 348 KB Output is correct
15 Correct 1 ms 604 KB Output is correct
16 Correct 1 ms 604 KB Output is correct
17 Correct 0 ms 604 KB Output is correct
18 Correct 1 ms 604 KB Output is correct
19 Correct 1 ms 604 KB Output is correct
20 Correct 1 ms 604 KB Output is correct
21 Correct 1 ms 604 KB Output is correct
22 Correct 0 ms 456 KB Output is correct
23 Correct 0 ms 348 KB Output is correct
24 Correct 1 ms 604 KB Output is correct
25 Correct 1 ms 604 KB Output is correct
26 Correct 1 ms 604 KB Output is correct
27 Correct 1 ms 604 KB Output is correct
28 Correct 1 ms 604 KB Output is correct
29 Correct 1 ms 604 KB Output is correct
30 Correct 1 ms 604 KB Output is correct
31 Correct 23 ms 3264 KB Output is correct
32 Correct 19 ms 3160 KB Output is correct
33 Correct 24 ms 3416 KB Output is correct
34 Correct 23 ms 3420 KB Output is correct
35 Correct 17 ms 3420 KB Output is correct
36 Correct 16 ms 3412 KB Output is correct
37 Correct 18 ms 2908 KB Output is correct
38 Correct 0 ms 348 KB Output is correct
39 Correct 0 ms 348 KB Output is correct
40 Correct 1 ms 604 KB Output is correct
41 Correct 1 ms 604 KB Output is correct
42 Correct 1 ms 604 KB Output is correct
43 Correct 1 ms 604 KB Output is correct
44 Correct 1 ms 604 KB Output is correct
45 Correct 1 ms 600 KB Output is correct
46 Correct 1 ms 604 KB Output is correct
47 Correct 50 ms 28984 KB Output is correct
48 Correct 47 ms 28228 KB Output is correct
49 Correct 54 ms 28740 KB Output is correct
50 Correct 53 ms 28988 KB Output is correct
51 Correct 52 ms 28872 KB Output is correct
52 Correct 49 ms 28992 KB Output is correct
53 Correct 33 ms 28356 KB Output is correct
54 Correct 59 ms 27736 KB Output is correct
55 Correct 66 ms 27608 KB Output is correct
56 Correct 66 ms 27608 KB Output is correct
57 Correct 63 ms 28224 KB Output is correct
58 Correct 70 ms 27888 KB Output is correct
59 Correct 82 ms 27716 KB Output is correct
60 Correct 78 ms 27620 KB Output is correct
61 Correct 76 ms 27948 KB Output is correct
62 Correct 41 ms 26956 KB Output is correct
63 Correct 63 ms 27412 KB Output is correct
64 Correct 69 ms 27200 KB Output is correct
65 Correct 66 ms 27340 KB Output is correct
66 Correct 0 ms 348 KB Output is correct
67 Correct 81 ms 31184 KB Output is correct
68 Correct 73 ms 30756 KB Output is correct
69 Correct 74 ms 30788 KB Output is correct
70 Correct 73 ms 30780 KB Output is correct
71 Correct 71 ms 30784 KB Output is correct
72 Correct 71 ms 30804 KB Output is correct
73 Correct 68 ms 31188 KB Output is correct
74 Correct 69 ms 31156 KB Output is correct
75 Correct 79 ms 31180 KB Output is correct
76 Correct 85 ms 31156 KB Output is correct
77 Correct 52 ms 30532 KB Output is correct
78 Correct 0 ms 344 KB Output is correct
79 Correct 1 ms 604 KB Output is correct
80 Correct 2 ms 604 KB Output is correct
81 Correct 1 ms 716 KB Output is correct
82 Correct 1 ms 600 KB Output is correct
83 Correct 1 ms 604 KB Output is correct
84 Correct 1 ms 604 KB Output is correct
85 Correct 1 ms 604 KB Output is correct
86 Correct 21 ms 3164 KB Output is correct
87 Correct 19 ms 3200 KB Output is correct
88 Correct 24 ms 3420 KB Output is correct
89 Correct 19 ms 3416 KB Output is correct
90 Correct 17 ms 3420 KB Output is correct
91 Correct 16 ms 3416 KB Output is correct
92 Correct 23 ms 3100 KB Output is correct
93 Correct 56 ms 28924 KB Output is correct
94 Correct 47 ms 28224 KB Output is correct
95 Correct 56 ms 28928 KB Output is correct
96 Correct 52 ms 28996 KB Output is correct
97 Correct 47 ms 28992 KB Output is correct
98 Correct 50 ms 29044 KB Output is correct
99 Correct 34 ms 28220 KB Output is correct
100 Correct 85 ms 30788 KB Output is correct
101 Correct 83 ms 30788 KB Output is correct
102 Correct 77 ms 31044 KB Output is correct
103 Correct 68 ms 30528 KB Output is correct
104 Correct 66 ms 30400 KB Output is correct
105 Correct 67 ms 30532 KB Output is correct
106 Correct 77 ms 30128 KB Output is correct
107 Correct 83 ms 30148 KB Output is correct
108 Correct 86 ms 31048 KB Output is correct
109 Correct 75 ms 30800 KB Output is correct
110 Correct 77 ms 30800 KB Output is correct
111 Correct 76 ms 30784 KB Output is correct