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Submission #860594

# Submission time Handle Problem Language Result Execution time Memory
860594 2023-10-13T12:30:00 Z E869120 Event Hopping (BOI22_events) C++14
100 / 100
 321 ms 26856 KB 
#include <bits/stdc++.h>
using namespace std;

class RangeMin {
    public:
    int size_ = 1;
    vector<pair<int, int>> dat;

    void init(int sz) {
        while (size_ <= sz) size_ *= 2;
        dat.resize(size_ * 2, make_pair(0, 0));
    }

    void update(int pos, pair<int, int> val) {
        pos += size_;
        dat[pos] = val;
        while (pos >= 2) {
            pos >>= 1;
            dat[pos] = min(dat[pos * 2 + 0], dat[pos * 2 + 1]);
        }
    }

    pair<int, int> query_(int l, int r, int a, int b, int u) {
        if (l <= a && b <= r) return dat[u];
        if (r <= a || b <= l) return make_pair(2000000000, -1);
        pair<int, int> v1 = query_(l, r, a, (a + b) / 2, u * 2 + 0);
        pair<int, int> v2 = query_(l, r, (a + b) / 2, b, u * 2 + 1);
        return min(v1, v2);
    }

    pair<int, int> query(int l, int r) {
        return query_(l, r, 0, size_, 1);
    }
};

int N, S[1 << 19], T[1 << 19];
int Q, X[1 << 19], Y[1 << 19];
int Prev[1 << 19][22];

int solve(int stt, int goa) {
    if (T[stt] > T[goa]) return -1;
    if (stt == goa) return 0;
    if (T[stt] >= S[goa]) return 1;

    // Doubling
    int cx = goa, cur = 0;
    for (int d = 21; d >= 0; d--) {
        int nex = Prev[cx][d];
        if (S[nex] > T[stt]) { cx = nex; cur += (1 << d); }
    }
    if (cur >= (1 << 21)) return -1;
    return cur + 2;
}

int main() {
    // Step 1. Input
    cin >> N >> Q;
    for (int i = 1; i <= N; i++) cin >> S[i] >> T[i];
    for (int i = 1; i <= Q; i++) cin >> X[i] >> Y[i];

    // Step 2. Sorting
    vector<tuple<int, int, int>> List;
    for (int i = 1; i <= N; i++) List.push_back(make_tuple(T[i], S[i], i));
    sort(List.begin(), List.end());
    RangeMin Z; Z.init(List.size() + 2);
    for (int i = 0; i < (int)List.size(); i++) {
        Z.update(i, make_pair(get<1>(List[i]), get<2>(List[i])));
    }

    // Step 3. Get Prev
    for (int i = 0; i < (int)List.size(); i++) {
        int idx = get<2>(List[i]);
        int pos1 = lower_bound(List.begin(), List.end(), make_tuple(S[idx], -1, -1)) - List.begin();
        pair<int, int> ret = Z.query(pos1, i);
        if (ret.first == 2000000000) Prev[idx][0] = idx;
        else Prev[idx][0] = ret.second;
    }

    // Step 4. Doubling
    for (int d = 1; d <= 21; d++) {
        for (int i = 1; i <= N; i++) Prev[i][d] = Prev[Prev[i][d - 1]][d - 1];
    }

    // Step 5. Answer Query
    for (int i = 1; i <= Q; i++) {
        int ret = solve(X[i], Y[i]);
        if (ret == -1) cout << "impossible" << endl;
        else cout << ret << endl;
    }
    return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8536 KB Output is correct
2 Correct 246 ms 26312 KB Output is correct
3 Correct 267 ms 26480 KB Output is correct
4 Correct 276 ms 26248 KB Output is correct
5 Correct 256 ms 26388 KB Output is correct
6 Correct 253 ms 26564 KB Output is correct
7 Correct 253 ms 26304 KB Output is correct
8 Correct 248 ms 26816 KB Output is correct
9 Correct 253 ms 26820 KB Output is correct
10 Correct 255 ms 26472 KB Output is correct
11 Correct 261 ms 26720 KB Output is correct
12 Correct 270 ms 25836 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8536 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8796 KB Output is correct
4 Correct 2 ms 8648 KB Output is correct
5 Correct 2 ms 8540 KB Output is correct
6 Correct 3 ms 8796 KB Output is correct
7 Correct 2 ms 8792 KB Output is correct
8 Correct 2 ms 8796 KB Output is correct
9 Correct 2 ms 8540 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8536 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8796 KB Output is correct
4 Correct 2 ms 8648 KB Output is correct
5 Correct 2 ms 8540 KB Output is correct
6 Correct 3 ms 8796 KB Output is correct
7 Correct 2 ms 8792 KB Output is correct
8 Correct 2 ms 8796 KB Output is correct
9 Correct 2 ms 8540 KB Output is correct
10 Correct 1 ms 8540 KB Output is correct
11 Correct 1 ms 8540 KB Output is correct
12 Correct 2 ms 8796 KB Output is correct
13 Correct 3 ms 8796 KB Output is correct
14 Correct 2 ms 8540 KB Output is correct
15 Correct 2 ms 8540 KB Output is correct
16 Correct 3 ms 8796 KB Output is correct
17 Correct 2 ms 8540 KB Output is correct
18 Correct 2 ms 8540 KB Output is correct
19 Correct 156 ms 12628 KB Output is correct
20 Correct 154 ms 12624 KB Output is correct
21 Correct 159 ms 13136 KB Output is correct
22 Correct 152 ms 13032 KB Output is correct
23 Correct 184 ms 12832 KB Output is correct
24 Correct 157 ms 12924 KB Output is correct
25 Correct 153 ms 12340 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 8536 KB Output is correct
2 Correct 1 ms 8540 KB Output is correct
3 Correct 2 ms 8796 KB Output is correct
4 Correct 2 ms 8648 KB Output is correct
5 Correct 2 ms 8540 KB Output is correct
6 Correct 3 ms 8796 KB Output is correct
7 Correct 2 ms 8792 KB Output is correct
8 Correct 2 ms 8796 KB Output is correct
9 Correct 2 ms 8540 KB Output is correct
10 Correct 1 ms 8536 KB Output is correct
11 Correct 1 ms 8540 KB Output is correct
12 Correct 3 ms 8540 KB Output is correct
13 Correct 2 ms 8656 KB Output is correct
14 Correct 2 ms 8540 KB Output is correct
15 Correct 3 ms 8540 KB Output is correct
16 Correct 2 ms 8796 KB Output is correct
17 Correct 2 ms 8644 KB Output is correct
18 Correct 2 ms 8540 KB Output is correct
19 Correct 97 ms 24604 KB Output is correct
20 Correct 79 ms 23756 KB Output is correct
21 Correct 103 ms 24260 KB Output is correct
22 Correct 96 ms 24520 KB Output is correct
23 Correct 89 ms 24516 KB Output is correct
24 Correct 124 ms 24344 KB Output is correct
25 Correct 70 ms 23700 KB Output is correct

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 251 ms 26340 KB Output is correct
2 Correct 260 ms 26308 KB Output is correct
3 Correct 279 ms 26128 KB Output is correct
4 Correct 279 ms 26652 KB Output is correct
5 Correct 261 ms 26716 KB Output is correct
6 Correct 279 ms 26348 KB Output is correct
7 Correct 259 ms 26224 KB Output is correct
8 Correct 264 ms 26496 KB Output is correct
9 Correct 89 ms 24384 KB Output is correct
10 Correct 255 ms 26056 KB Output is correct
11 Correct 261 ms 25792 KB Output is correct
12 Correct 279 ms 26044 KB Output is correct

Subtask #6
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 8536 KB Output is correct
2 Correct 246 ms 26312 KB Output is correct
3 Correct 267 ms 26480 KB Output is correct
4 Correct 276 ms 26248 KB Output is correct
5 Correct 256 ms 26388 KB Output is correct
6 Correct 253 ms 26564 KB Output is correct
7 Correct 253 ms 26304 KB Output is correct
8 Correct 248 ms 26816 KB Output is correct
9 Correct 253 ms 26820 KB Output is correct
10 Correct 255 ms 26472 KB Output is correct
11 Correct 261 ms 26720 KB Output is correct
12 Correct 270 ms 25836 KB Output is correct
13 Correct 1 ms 8536 KB Output is correct
14 Correct 1 ms 8540 KB Output is correct
15 Correct 2 ms 8796 KB Output is correct
16 Correct 2 ms 8648 KB Output is correct
17 Correct 2 ms 8540 KB Output is correct
18 Correct 3 ms 8796 KB Output is correct
19 Correct 2 ms 8792 KB Output is correct
20 Correct 2 ms 8796 KB Output is correct
21 Correct 2 ms 8540 KB Output is correct
22 Correct 1 ms 8540 KB Output is correct
23 Correct 1 ms 8540 KB Output is correct
24 Correct 2 ms 8796 KB Output is correct
25 Correct 3 ms 8796 KB Output is correct
26 Correct 2 ms 8540 KB Output is correct
27 Correct 2 ms 8540 KB Output is correct
28 Correct 3 ms 8796 KB Output is correct
29 Correct 2 ms 8540 KB Output is correct
30 Correct 2 ms 8540 KB Output is correct
31 Correct 156 ms 12628 KB Output is correct
32 Correct 154 ms 12624 KB Output is correct
33 Correct 159 ms 13136 KB Output is correct
34 Correct 152 ms 13032 KB Output is correct
35 Correct 184 ms 12832 KB Output is correct
36 Correct 157 ms 12924 KB Output is correct
37 Correct 153 ms 12340 KB Output is correct
38 Correct 1 ms 8536 KB Output is correct
39 Correct 1 ms 8540 KB Output is correct
40 Correct 3 ms 8540 KB Output is correct
41 Correct 2 ms 8656 KB Output is correct
42 Correct 2 ms 8540 KB Output is correct
43 Correct 3 ms 8540 KB Output is correct
44 Correct 2 ms 8796 KB Output is correct
45 Correct 2 ms 8644 KB Output is correct
46 Correct 2 ms 8540 KB Output is correct
47 Correct 97 ms 24604 KB Output is correct
48 Correct 79 ms 23756 KB Output is correct
49 Correct 103 ms 24260 KB Output is correct
50 Correct 96 ms 24520 KB Output is correct
51 Correct 89 ms 24516 KB Output is correct
52 Correct 124 ms 24344 KB Output is correct
53 Correct 70 ms 23700 KB Output is correct
54 Correct 251 ms 26340 KB Output is correct
55 Correct 260 ms 26308 KB Output is correct
56 Correct 279 ms 26128 KB Output is correct
57 Correct 279 ms 26652 KB Output is correct
58 Correct 261 ms 26716 KB Output is correct
59 Correct 279 ms 26348 KB Output is correct
60 Correct 259 ms 26224 KB Output is correct
61 Correct 264 ms 26496 KB Output is correct
62 Correct 89 ms 24384 KB Output is correct
63 Correct 255 ms 26056 KB Output is correct
64 Correct 261 ms 25792 KB Output is correct
65 Correct 279 ms 26044 KB Output is correct
66 Correct 1 ms 8536 KB Output is correct
67 Correct 278 ms 26428 KB Output is correct
68 Correct 248 ms 26308 KB Output is correct
69 Correct 273 ms 26308 KB Output is correct
70 Correct 256 ms 26308 KB Output is correct
71 Correct 256 ms 26380 KB Output is correct
72 Correct 259 ms 26580 KB Output is correct
73 Correct 250 ms 26740 KB Output is correct
74 Correct 249 ms 26856 KB Output is correct
75 Correct 270 ms 26524 KB Output is correct
76 Correct 273 ms 26628 KB Output is correct
77 Correct 226 ms 25916 KB Output is correct
78 Correct 1 ms 8540 KB Output is correct
79 Correct 2 ms 8668 KB Output is correct
80 Correct 2 ms 8796 KB Output is correct
81 Correct 2 ms 8540 KB Output is correct
82 Correct 2 ms 8656 KB Output is correct
83 Correct 2 ms 8540 KB Output is correct
84 Correct 2 ms 8796 KB Output is correct
85 Correct 2 ms 8540 KB Output is correct
86 Correct 157 ms 12448 KB Output is correct
87 Correct 152 ms 12624 KB Output is correct
88 Correct 157 ms 12888 KB Output is correct
89 Correct 159 ms 12884 KB Output is correct
90 Correct 151 ms 12628 KB Output is correct
91 Correct 152 ms 12812 KB Output is correct
92 Correct 156 ms 12564 KB Output is correct
93 Correct 100 ms 24600 KB Output is correct
94 Correct 80 ms 23784 KB Output is correct
95 Correct 104 ms 24260 KB Output is correct
96 Correct 105 ms 24836 KB Output is correct
97 Correct 88 ms 24568 KB Output is correct
98 Correct 99 ms 24520 KB Output is correct
99 Correct 70 ms 23744 KB Output is correct
100 Correct 263 ms 26632 KB Output is correct
101 Correct 271 ms 26308 KB Output is correct
102 Correct 321 ms 26608 KB Output is correct
103 Correct 264 ms 26052 KB Output is correct
104 Correct 248 ms 25732 KB Output is correct
105 Correct 286 ms 26276 KB Output is correct
106 Correct 256 ms 25604 KB Output is correct
107 Correct 277 ms 25796 KB Output is correct
108 Correct 257 ms 26312 KB Output is correct
109 Correct 256 ms 26568 KB Output is correct
110 Correct 265 ms 26304 KB Output is correct
111 Correct 263 ms 26324 KB Output is correct