답안 #644816

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
644816	2022-09-25T09:45:34 Z	FedShat	Event Hopping (BOI22_events)	C++17	100 / 100	191 ms	21740 KB

events

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
constexpr int INF = numeric_limits<int>::max() / 2;
constexpr ll INFLL = numeric_limits<ll>::max() / 2;

template<class T>
istream &operator>>(istream &is, vector<T> &a) {
    for (auto &i : a) {
        is >> i;
    }
    return is;
}

struct SegTree {
    vector<pair<int, int>> tree;
    int n;

    SegTree(int n) : n(n) {
        tree.resize(4 * n, {INF, -1});
    }

    void update(int v, int l, int r, int i, pair<int, int> x) {
        if (l + 1 == r) {
            tree[v] = min(tree[v], x);
            return;
        }
        int m = (l + r) / 2;
        if (i < m) {
            update(2 * v + 1, l, m, i, x);
        } else {
            update(2 * v + 2, m, r, i, x);
        }
        tree[v] = min(tree[2 * v + 1], tree[2 * v + 2]);
    }

    void update(int i, pair<int, int> x) {
        update(0, 0, n, i, x);
    }

    pair<int, int> get(int v, int l, int r, int li, int ri) {
        if (li >= r || l >= ri) {
            return {INF, -1};
        }
        if (li <= l && r <= ri) {
            return tree[v];
        }
        int m = (l + r) / 2;
        return min(get(2 * v + 1, l, m, li, ri), get(2 * v + 2, m, r, li, ri));
    }

    int get(int li, int ri) {
        return get(0, 0, n, li, ri).second;
    }
};

int main() {
    cin.tie(0)->sync_with_stdio(0);
#ifdef __APPLE__
    freopen("input.txt", "r", stdin);
#endif
    int n, q;
    cin >> n >> q;
    vector<array<int, 3>> lr(n);
    vector<int> coords;
    for (int i = 0; i < n; ++i) {
        cin >> lr[i][0] >> lr[i][1];
        lr[i][2] = i;
        coords.push_back(lr[i][0]);
        coords.push_back(lr[i][1]);
    }
    sort(coords.begin(), coords.end());
    coords.resize(unique(coords.begin(), coords.end()) - coords.begin());
    sort(lr.begin(), lr.end());
    vector<int> p(n);
    for (int i = 0; i < n; ++i) {
        p[lr[i][2]] = i;
    }
    for (int i = 0; i < n; ++i) {
        auto &[l, r, ii] = lr[i];
        l = lower_bound(coords.begin(), coords.end(), l) - coords.begin();
        r = lower_bound(coords.begin(), coords.end(), r) - coords.begin();
    }
    SegTree t(coords.size());
    auto can = [&](int i, int j) {// i -> j
        auto [li, ri, ii] = lr[i];
        auto [lj, rj, jj] = lr[j];
        return lj <= ri && ri <= rj;
    };
    vector<int> prv(n);
    for (int i = 0; i < n; ++i) {
        // int ind = -1;
        // for (int j = 0; j < i; ++j) {
        //     if (can(j, i)) {
        //         ind = j;
        //         break;
        //     }
        // }
        // prv[i] = ind;
        auto [l, r, _] = lr[i];
        prv[i] = t.get(l, r + 1);
        t.update(r, {l, i});
    }
    constexpr int k = 20;
    vector<vector<int>> up(k, vector<int>(n, -1));
    up[0] = prv;
    for (int i = 1; i < k; ++i) {
        for (int j = 0; j < n; ++j) {
            if (up[i - 1][j] != -1) {
                up[i][j] = up[i - 1][up[i - 1][j]];
            }
        }
    }
    while (q--) {
        int a, b;
        cin >> a >> b;
        --a;
        --b;
        a = p[a];
        b = p[b];
        int ans = 0;
        for (int i = k - 1; i >= 0; --i) {
            if (up[i][b] != -1 && !can(a, up[i][b]) && lr[up[i][b]][0] > lr[a][1]) {
                b = up[i][b];
                ans += (1 << i);
            }
        }
        if (!can(a, b)) {
            b = up[0][b];
            ++ans;
        }
        if (b == -1 || !can(a, b)) {
            ans = -1;
        } else if (a != b) {
            ++ans;
        }
        if (ans == -1) {
            cout << "impossible\n";
        } else {
            cout << ans << "\n";
        }
    }
}

Subtask #1

10.0 / 10.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	212 KB	Output is correct
2	Correct	113 ms	14960 KB	Output is correct
3	Correct	110 ms	18004 KB	Output is correct
4	Correct	113 ms	18140 KB	Output is correct
5	Correct	117 ms	18368 KB	Output is correct
6	Correct	130 ms	18704 KB	Output is correct
7	Correct	118 ms	18888 KB	Output is correct
8	Correct	106 ms	21716 KB	Output is correct
9	Correct	108 ms	21732 KB	Output is correct
10	Correct	151 ms	18380 KB	Output is correct
11	Correct	160 ms	19700 KB	Output is correct
12	Correct	83 ms	17932 KB	Output is correct

Subtask #2

10.0 / 10.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	212 KB	Output is correct
2	Correct	0 ms	212 KB	Output is correct
3	Correct	1 ms	340 KB	Output is correct
4	Correct	1 ms	340 KB	Output is correct
5	Correct	1 ms	376 KB	Output is correct
6	Correct	1 ms	340 KB	Output is correct
7	Correct	2 ms	468 KB	Output is correct
8	Correct	1 ms	468 KB	Output is correct
9	Correct	1 ms	340 KB	Output is correct

Subtask #3

15.0 / 15.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	212 KB	Output is correct
2	Correct	0 ms	212 KB	Output is correct
3	Correct	1 ms	340 KB	Output is correct
4	Correct	1 ms	340 KB	Output is correct
5	Correct	1 ms	376 KB	Output is correct
6	Correct	1 ms	340 KB	Output is correct
7	Correct	2 ms	468 KB	Output is correct
8	Correct	1 ms	468 KB	Output is correct
9	Correct	1 ms	340 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	468 KB	Output is correct
13	Correct	1 ms	340 KB	Output is correct
14	Correct	1 ms	340 KB	Output is correct
15	Correct	1 ms	468 KB	Output is correct
16	Correct	1 ms	468 KB	Output is correct
17	Correct	1 ms	468 KB	Output is correct
18	Correct	1 ms	340 KB	Output is correct
19	Correct	38 ms	1484 KB	Output is correct
20	Correct	29 ms	1484 KB	Output is correct
21	Correct	41 ms	1760 KB	Output is correct
22	Correct	32 ms	1824 KB	Output is correct
23	Correct	32 ms	1772 KB	Output is correct
24	Correct	26 ms	1832 KB	Output is correct
25	Correct	27 ms	1364 KB	Output is correct

Subtask #4

15.0 / 15.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	212 KB	Output is correct
2	Correct	0 ms	212 KB	Output is correct
3	Correct	1 ms	340 KB	Output is correct
4	Correct	1 ms	340 KB	Output is correct
5	Correct	1 ms	376 KB	Output is correct
6	Correct	1 ms	340 KB	Output is correct
7	Correct	2 ms	468 KB	Output is correct
8	Correct	1 ms	468 KB	Output is correct
9	Correct	1 ms	340 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	340 KB	Output is correct
13	Correct	1 ms	340 KB	Output is correct
14	Correct	1 ms	340 KB	Output is correct
15	Correct	1 ms	340 KB	Output is correct
16	Correct	1 ms	468 KB	Output is correct
17	Correct	1 ms	468 KB	Output is correct
18	Correct	1 ms	340 KB	Output is correct
19	Correct	80 ms	14284 KB	Output is correct
20	Correct	76 ms	14388 KB	Output is correct
21	Correct	118 ms	14308 KB	Output is correct
22	Correct	92 ms	15540 KB	Output is correct
23	Correct	100 ms	17512 KB	Output is correct
24	Correct	98 ms	17516 KB	Output is correct
25	Correct	35 ms	11224 KB	Output is correct

Subtask #5

20.0 / 20.0

#	결과	실행 시간	메모리	Grader output
1	Correct	131 ms	14976 KB	Output is correct
2	Correct	108 ms	18104 KB	Output is correct
3	Correct	117 ms	18004 KB	Output is correct
4	Correct	105 ms	21740 KB	Output is correct
5	Correct	152 ms	18392 KB	Output is correct
6	Correct	148 ms	21416 KB	Output is correct
7	Correct	180 ms	21384 KB	Output is correct
8	Correct	171 ms	21432 KB	Output is correct
9	Correct	92 ms	19448 KB	Output is correct
10	Correct	124 ms	20956 KB	Output is correct
11	Correct	123 ms	20820 KB	Output is correct
12	Correct	130 ms	20912 KB	Output is correct

Subtask #6

30.0 / 30.0

#	결과	실행 시간	메모리	Grader output
1	Correct	0 ms	212 KB	Output is correct
2	Correct	113 ms	14960 KB	Output is correct
3	Correct	110 ms	18004 KB	Output is correct
4	Correct	113 ms	18140 KB	Output is correct
5	Correct	117 ms	18368 KB	Output is correct
6	Correct	130 ms	18704 KB	Output is correct
7	Correct	118 ms	18888 KB	Output is correct
8	Correct	106 ms	21716 KB	Output is correct
9	Correct	108 ms	21732 KB	Output is correct
10	Correct	151 ms	18380 KB	Output is correct
11	Correct	160 ms	19700 KB	Output is correct
12	Correct	83 ms	17932 KB	Output is correct
13	Correct	0 ms	212 KB	Output is correct
14	Correct	0 ms	212 KB	Output is correct
15	Correct	1 ms	340 KB	Output is correct
16	Correct	1 ms	340 KB	Output is correct
17	Correct	1 ms	376 KB	Output is correct
18	Correct	1 ms	340 KB	Output is correct
19	Correct	2 ms	468 KB	Output is correct
20	Correct	1 ms	468 KB	Output is correct
21	Correct	1 ms	340 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	468 KB	Output is correct
25	Correct	1 ms	340 KB	Output is correct
26	Correct	1 ms	340 KB	Output is correct
27	Correct	1 ms	468 KB	Output is correct
28	Correct	1 ms	468 KB	Output is correct
29	Correct	1 ms	468 KB	Output is correct
30	Correct	1 ms	340 KB	Output is correct
31	Correct	38 ms	1484 KB	Output is correct
32	Correct	29 ms	1484 KB	Output is correct
33	Correct	41 ms	1760 KB	Output is correct
34	Correct	32 ms	1824 KB	Output is correct
35	Correct	32 ms	1772 KB	Output is correct
36	Correct	26 ms	1832 KB	Output is correct
37	Correct	27 ms	1364 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	340 KB	Output is correct
41	Correct	1 ms	340 KB	Output is correct
42	Correct	1 ms	340 KB	Output is correct
43	Correct	1 ms	340 KB	Output is correct
44	Correct	1 ms	468 KB	Output is correct
45	Correct	1 ms	468 KB	Output is correct
46	Correct	1 ms	340 KB	Output is correct
47	Correct	80 ms	14284 KB	Output is correct
48	Correct	76 ms	14388 KB	Output is correct
49	Correct	118 ms	14308 KB	Output is correct
50	Correct	92 ms	15540 KB	Output is correct
51	Correct	100 ms	17512 KB	Output is correct
52	Correct	98 ms	17516 KB	Output is correct
53	Correct	35 ms	11224 KB	Output is correct
54	Correct	131 ms	14976 KB	Output is correct
55	Correct	108 ms	18104 KB	Output is correct
56	Correct	117 ms	18004 KB	Output is correct
57	Correct	105 ms	21740 KB	Output is correct
58	Correct	152 ms	18392 KB	Output is correct
59	Correct	148 ms	21416 KB	Output is correct
60	Correct	180 ms	21384 KB	Output is correct
61	Correct	171 ms	21432 KB	Output is correct
62	Correct	92 ms	19448 KB	Output is correct
63	Correct	124 ms	20956 KB	Output is correct
64	Correct	123 ms	20820 KB	Output is correct
65	Correct	130 ms	20912 KB	Output is correct
66	Correct	1 ms	212 KB	Output is correct
67	Correct	127 ms	18068 KB	Output is correct
68	Correct	110 ms	18032 KB	Output is correct
69	Correct	120 ms	17984 KB	Output is correct
70	Correct	120 ms	18460 KB	Output is correct
71	Correct	130 ms	18800 KB	Output is correct
72	Correct	124 ms	18900 KB	Output is correct
73	Correct	122 ms	21720 KB	Output is correct
74	Correct	119 ms	21720 KB	Output is correct
75	Correct	163 ms	18468 KB	Output is correct
76	Correct	176 ms	19744 KB	Output is correct
77	Correct	112 ms	17836 KB	Output is correct
78	Correct	1 ms	212 KB	Output is correct
79	Correct	1 ms	468 KB	Output is correct
80	Correct	1 ms	468 KB	Output is correct
81	Correct	1 ms	468 KB	Output is correct
82	Correct	1 ms	468 KB	Output is correct
83	Correct	1 ms	468 KB	Output is correct
84	Correct	1 ms	468 KB	Output is correct
85	Correct	1 ms	332 KB	Output is correct
86	Correct	38 ms	2448 KB	Output is correct
87	Correct	43 ms	2508 KB	Output is correct
88	Correct	40 ms	2668 KB	Output is correct
89	Correct	35 ms	2864 KB	Output is correct
90	Correct	39 ms	2756 KB	Output is correct
91	Correct	31 ms	2852 KB	Output is correct
92	Correct	34 ms	2480 KB	Output is correct
93	Correct	88 ms	16344 KB	Output is correct
94	Correct	106 ms	15536 KB	Output is correct
95	Correct	115 ms	16168 KB	Output is correct
96	Correct	90 ms	17496 KB	Output is correct
97	Correct	96 ms	19452 KB	Output is correct
98	Correct	99 ms	19504 KB	Output is correct
99	Correct	43 ms	12436 KB	Output is correct
100	Correct	156 ms	21336 KB	Output is correct
101	Correct	162 ms	21448 KB	Output is correct
102	Correct	169 ms	21508 KB	Output is correct
103	Correct	117 ms	20976 KB	Output is correct
104	Correct	145 ms	20820 KB	Output is correct
105	Correct	121 ms	20948 KB	Output is correct
106	Correct	142 ms	16764 KB	Output is correct
107	Correct	172 ms	17428 KB	Output is correct
108	Correct	157 ms	18204 KB	Output is correct
109	Correct	147 ms	18132 KB	Output is correct
110	Correct	168 ms	21212 KB	Output is correct
111	Correct	191 ms	21264 KB	Output is correct