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Submission #597591

# Submission time Handle Problem Language Result Execution time Memory
597591 2022-07-16T11:09:05 Z boris_mihov Event Hopping (BOI22_events) C++14
100 / 100
 106 ms 17872 KB 
#include <algorithm>
#include <iostream>
#include <numeric>

const int MAXN = 100000 + 10;
const int MAXLOG = 18;
const int INF = 1e9 + 10;

struct Event
{
    int s, e;
    inline friend bool operator < (Event a, Event b)
    {
        return a.s < b.s || (a.s == b.s && a.e < b.e);
    }
} ev[MAXN];

int n, q;
int getLog[MAXN];
int rmq[MAXLOG][MAXN];
int lift[MAXLOG][MAXN];
int perm[MAXN], newNum[MAXN];

int cmp(int x, int y)
{
    if (ev[x].e >= ev[y].e) return x;
    return y;
}

void buildRMQ()
{
    std::iota(rmq[0]+1, rmq[0]+1+n, 1);
    for (int log = 1 ; (1 << log) <= n ; ++log)
    {
        for (int i = 1 ; i + (1 << log) - 1 <= n ; ++i)
        {
            rmq[log][i] = cmp(rmq[log-1][i], rmq[log-1][i + (1 << log-1)]);
        }
    }

    for (int i = 1 ; i <= n ; ++i)
    {
        getLog[i] = getLog[i-1];
        if ((1 << getLog[i]+1) < i) ++getLog[i];
    }
}

int upperBinSearch(int value)
{
    int l = 1, r = n+1, mid;
    while (l < r - 1)
    {
        mid = (l + r) / 2;
        if (ev[mid].s <= value) l = mid;
        else r = mid;
    }

    return l;
}

int lowerBinSearch(int idx)
{
    int l = 0, r = n, mid;
    while (l < r - 1)
    {
        mid = (l + r) / 2;
        if (mid <= idx || ev[mid].s < ev[idx].s) l = mid;
        else r = mid;
    }

    return r;
}

int findMaximum(int l, int r)
{
    int log = getLog[r-l+1];
    return cmp(rmq[log][l], rmq[log][r - (1 << log) + 1]);
}

void buildLift()
{
    for (int log = 1 ; (1 << log) <= n ; ++log)
    {
        for (int i = 1 ; i <= n ; ++i)
        {
            lift[log][i] = lift[log-1][lift[log-1][i]];
        }
    }
}

int binaryLifting(int from, int value)
{
    if (ev[from].s > value) return -1;
    if (ev[from].e >= value) return 1;
    int ans = 2;
    for (int log = MAXLOG-1 ; log >= 0 ; --log)
    {
        if (lift[log][from] == 0) continue;
        if (ev[lift[log][from]].e < value)
        {
            ans += (1 << log);
            from = lift[log][from];   
        }
    }

    if (ev[lift[0][from]].e < value) return -1;
    else return ans;
}

void solve()
{
    std::iota(perm+1, perm+1+n, 1);
    std::sort(perm+1, perm+1+n, [&](int x, int y)
    {
        return ev[x] < ev[y];
    });

    for (int i = 1 ; i <= n ; ++i)
    {
        newNum[perm[i]] = i;
    }

    std::sort(ev+1, ev+1+n);
    buildRMQ();

    for (int i = 1 ; i <= n ; ++i)
    {
        int from = lowerBinSearch(i);
        int to = upperBinSearch(ev[i].e);
        if (i+1 <= from && from <= to && from >= 1 && to <= n)
        {
            int jump = findMaximum(from, to);
            lift[0][i] = jump;
            if (i == jump) lift[0][i] = 0;
        }
    }

    buildLift();
    for (int i = 1 ; i <= q ; ++i)
    {
        int st, en;
        std::cin >> st >> en; 
        std::swap(st, en);
       
        if (st == en)
        {
            std::cout << 0 << '\n';
            continue;
        }

        st = newNum[st];
        en = ev[newNum[en]].s;
        int res = binaryLifting(st, en);
        if (res == -1) std::cout << "impossible\n";
        else std::cout << res << '\n';
    }
}

void read()
{
    std::cin >> n >> q;
    for (int i = 1 ; i <= n ; ++i)
    {
        std::cin >> ev[i].s >> ev[i].e;
        ev[i].s = INF - ev[i].s;
        ev[i].e = INF - ev[i].e;
        std::swap(ev[i].s, ev[i].e);
    }
}

void fastIO()
{
    std::ios_base :: sync_with_stdio(0);
    std::cout.tie(nullptr);
    std::cin.tie(nullptr);
}

int main()
{
    fastIO();
    read();
    solve();

    return 0;
}

Compilation message

events.cpp: In function 'void buildRMQ()':
events.cpp:37:70: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
   37 |             rmq[log][i] = cmp(rmq[log-1][i], rmq[log-1][i + (1 << log-1)]);
      |                                                                   ~~~^~
events.cpp:44:28: warning: suggest parentheses around '+' inside '<<' [-Wparentheses]
   44 |         if ((1 << getLog[i]+1) < i) ++getLog[i];
      |                   ~~~~~~~~~^~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 76 ms 15700 KB Output is correct
3 Correct 78 ms 15692 KB Output is correct
4 Correct 89 ms 15744 KB Output is correct
5 Correct 82 ms 15692 KB Output is correct
6 Correct 80 ms 15748 KB Output is correct
7 Correct 78 ms 15752 KB Output is correct
8 Correct 73 ms 15712 KB Output is correct
9 Correct 74 ms 15708 KB Output is correct
10 Correct 101 ms 15948 KB Output is correct
11 Correct 95 ms 16104 KB Output is correct
12 Correct 57 ms 16204 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 ms 540 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 468 KB Output is correct
9 Correct 1 ms 468 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 ms 540 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 468 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 0 ms 340 KB Output is correct
11 Correct 0 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 468 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 468 KB Output is correct
19 Correct 28 ms 1492 KB Output is correct
20 Correct 25 ms 1500 KB Output is correct
21 Correct 30 ms 1744 KB Output is correct
22 Correct 23 ms 1748 KB Output is correct
23 Correct 24 ms 2652 KB Output is correct
24 Correct 22 ms 2644 KB Output is correct
25 Correct 24 ms 2296 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 ms 540 KB Output is correct
4 Correct 1 ms 468 KB Output is correct
5 Correct 1 ms 468 KB Output is correct
6 Correct 1 ms 468 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 468 KB Output is correct
9 Correct 1 ms 468 KB Output is correct
10 Correct 1 ms 340 KB Output is correct
11 Correct 1 ms 340 KB Output is correct
12 Correct 1 ms 468 KB Output is correct
13 Correct 1 ms 468 KB Output is correct
14 Correct 1 ms 468 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 468 KB Output is correct
19 Correct 52 ms 15052 KB Output is correct
20 Correct 49 ms 15060 KB Output is correct
21 Correct 59 ms 15068 KB Output is correct
22 Correct 56 ms 15072 KB Output is correct
23 Correct 50 ms 15028 KB Output is correct
24 Correct 53 ms 15052 KB Output is correct
25 Correct 36 ms 15068 KB Output is correct

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 74 ms 15636 KB Output is correct
2 Correct 78 ms 15704 KB Output is correct
3 Correct 83 ms 15684 KB Output is correct
4 Correct 72 ms 15748 KB Output is correct
5 Correct 95 ms 15968 KB Output is correct
6 Correct 97 ms 15820 KB Output is correct
7 Correct 94 ms 15820 KB Output is correct
8 Correct 92 ms 15864 KB Output is correct
9 Correct 51 ms 15000 KB Output is correct
10 Correct 77 ms 15468 KB Output is correct
11 Correct 74 ms 15228 KB Output is correct
12 Correct 79 ms 15436 KB Output is correct

Subtask #6
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 340 KB Output is correct
2 Correct 76 ms 15700 KB Output is correct
3 Correct 78 ms 15692 KB Output is correct
4 Correct 89 ms 15744 KB Output is correct
5 Correct 82 ms 15692 KB Output is correct
6 Correct 80 ms 15748 KB Output is correct
7 Correct 78 ms 15752 KB Output is correct
8 Correct 73 ms 15712 KB Output is correct
9 Correct 74 ms 15708 KB Output is correct
10 Correct 101 ms 15948 KB Output is correct
11 Correct 95 ms 16104 KB Output is correct
12 Correct 57 ms 16204 KB Output is correct
13 Correct 0 ms 340 KB Output is correct
14 Correct 0 ms 340 KB Output is correct
15 Correct 1 ms 540 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 468 KB Output is correct
19 Correct 1 ms 468 KB Output is correct
20 Correct 1 ms 468 KB Output is correct
21 Correct 1 ms 468 KB Output is correct
22 Correct 0 ms 340 KB Output is correct
23 Correct 0 ms 340 KB Output is correct
24 Correct 1 ms 468 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 468 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 468 KB Output is correct
31 Correct 28 ms 1492 KB Output is correct
32 Correct 25 ms 1500 KB Output is correct
33 Correct 30 ms 1744 KB Output is correct
34 Correct 23 ms 1748 KB Output is correct
35 Correct 24 ms 2652 KB Output is correct
36 Correct 22 ms 2644 KB Output is correct
37 Correct 24 ms 2296 KB Output is correct
38 Correct 1 ms 340 KB Output is correct
39 Correct 1 ms 340 KB Output is correct
40 Correct 1 ms 468 KB Output is correct
41 Correct 1 ms 468 KB Output is correct
42 Correct 1 ms 468 KB Output is correct
43 Correct 1 ms 468 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 468 KB Output is correct
47 Correct 52 ms 15052 KB Output is correct
48 Correct 49 ms 15060 KB Output is correct
49 Correct 59 ms 15068 KB Output is correct
50 Correct 56 ms 15072 KB Output is correct
51 Correct 50 ms 15028 KB Output is correct
52 Correct 53 ms 15052 KB Output is correct
53 Correct 36 ms 15068 KB Output is correct
54 Correct 74 ms 15636 KB Output is correct
55 Correct 78 ms 15704 KB Output is correct
56 Correct 83 ms 15684 KB Output is correct
57 Correct 72 ms 15748 KB Output is correct
58 Correct 95 ms 15968 KB Output is correct
59 Correct 97 ms 15820 KB Output is correct
60 Correct 94 ms 15820 KB Output is correct
61 Correct 92 ms 15864 KB Output is correct
62 Correct 51 ms 15000 KB Output is correct
63 Correct 77 ms 15468 KB Output is correct
64 Correct 74 ms 15228 KB Output is correct
65 Correct 79 ms 15436 KB Output is correct
66 Correct 1 ms 340 KB Output is correct
67 Correct 77 ms 17008 KB Output is correct
68 Correct 80 ms 17252 KB Output is correct
69 Correct 85 ms 17120 KB Output is correct
70 Correct 79 ms 17240 KB Output is correct
71 Correct 81 ms 17276 KB Output is correct
72 Correct 82 ms 17236 KB Output is correct
73 Correct 77 ms 17328 KB Output is correct
74 Correct 74 ms 17244 KB Output is correct
75 Correct 95 ms 17532 KB Output is correct
76 Correct 106 ms 17796 KB Output is correct
77 Correct 59 ms 17872 KB Output is correct
78 Correct 0 ms 340 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 476 KB Output is correct
86 Correct 29 ms 2424 KB Output is correct
87 Correct 26 ms 2508 KB Output is correct
88 Correct 30 ms 2768 KB Output is correct
89 Correct 24 ms 2736 KB Output is correct
90 Correct 24 ms 2636 KB Output is correct
91 Correct 22 ms 2568 KB Output is correct
92 Correct 27 ms 2240 KB Output is correct
93 Correct 55 ms 16692 KB Output is correct
94 Correct 49 ms 16132 KB Output is correct
95 Correct 65 ms 16772 KB Output is correct
96 Correct 55 ms 16740 KB Output is correct
97 Correct 52 ms 16724 KB Output is correct
98 Correct 55 ms 16580 KB Output is correct
99 Correct 36 ms 16276 KB Output is correct
100 Correct 101 ms 17296 KB Output is correct
101 Correct 102 ms 17356 KB Output is correct
102 Correct 96 ms 17448 KB Output is correct
103 Correct 78 ms 16972 KB Output is correct
104 Correct 80 ms 16860 KB Output is correct
105 Correct 77 ms 17152 KB Output is correct
106 Correct 92 ms 17416 KB Output is correct
107 Correct 106 ms 17484 KB Output is correct
108 Correct 91 ms 17488 KB Output is correct
109 Correct 93 ms 17376 KB Output is correct
110 Correct 91 ms 17192 KB Output is correct
111 Correct 91 ms 17372 KB Output is correct