oj.uz

Submission #597590

# Submission time Handle Problem Language Result Execution time Memory
597590 2022-07-16T11:06:48 Z boris_mihov Event Hopping (BOI22_events) C++14
55 / 100
 125 ms 16208 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;
    int ans = 1 + (ev[from].e < value);
    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 1 ms 340 KB Output is correct
2 Correct 85 ms 15700 KB Output is correct
3 Correct 83 ms 15692 KB Output is correct
4 Correct 84 ms 15580 KB Output is correct
5 Correct 78 ms 15712 KB Output is correct
6 Correct 82 ms 15760 KB Output is correct
7 Correct 78 ms 15704 KB Output is correct
8 Correct 81 ms 15744 KB Output is correct
9 Correct 79 ms 15756 KB Output is correct
10 Correct 94 ms 16044 KB Output is correct
11 Correct 93 ms 16208 KB Output is correct
12 Correct 59 ms 16200 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 388 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 ms 468 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
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 388 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 ms 468 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 29 ms 1500 KB Output is correct
20 Correct 33 ms 1476 KB Output is correct
21 Correct 32 ms 1740 KB Output is correct
22 Incorrect 24 ms 1748 KB Output isn't correct
23 Halted 0 ms 0 KB -

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 388 KB Output is correct
2 Correct 0 ms 340 KB Output is correct
3 Correct 1 ms 468 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 69 ms 15032 KB Output is correct
20 Correct 61 ms 15052 KB Output is correct
21 Correct 61 ms 15076 KB Output is correct
22 Correct 54 ms 15056 KB Output is correct
23 Correct 52 ms 15076 KB Output is correct
24 Correct 63 ms 14976 KB Output is correct
25 Correct 36 ms 15096 KB Output is correct

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 97 ms 15680 KB Output is correct
2 Correct 78 ms 15684 KB Output is correct
3 Correct 89 ms 15592 KB Output is correct
4 Correct 75 ms 15720 KB Output is correct
5 Correct 121 ms 16048 KB Output is correct
6 Correct 102 ms 15888 KB Output is correct
7 Correct 107 ms 15772 KB Output is correct
8 Correct 125 ms 15892 KB Output is correct
9 Correct 50 ms 15056 KB Output is correct
10 Correct 87 ms 15432 KB Output is correct
11 Correct 79 ms 15224 KB Output is correct
12 Correct 79 ms 15448 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 85 ms 15700 KB Output is correct
3 Correct 83 ms 15692 KB Output is correct
4 Correct 84 ms 15580 KB Output is correct
5 Correct 78 ms 15712 KB Output is correct
6 Correct 82 ms 15760 KB Output is correct
7 Correct 78 ms 15704 KB Output is correct
8 Correct 81 ms 15744 KB Output is correct
9 Correct 79 ms 15756 KB Output is correct
10 Correct 94 ms 16044 KB Output is correct
11 Correct 93 ms 16208 KB Output is correct
12 Correct 59 ms 16200 KB Output is correct
13 Correct 1 ms 388 KB Output is correct
14 Correct 0 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 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 29 ms 1500 KB Output is correct
32 Correct 33 ms 1476 KB Output is correct
33 Correct 32 ms 1740 KB Output is correct
34 Incorrect 24 ms 1748 KB Output isn't correct
35 Halted 0 ms 0 KB -