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Submission #864269

# Submission time Handle Problem Language Result Execution time Memory
864269 2023-10-22T09:43:33 Z danikoynov Event Hopping (BOI22_events) C++14
40 / 100
 1500 ms 9396 KB 
#include<bits/stdc++.h>

using namespace std;

const int maxn = 1e5 + 10;
     
struct interval
{
    int s, e, idx;
}seg[maxn];
     
struct query
{
    int start, finish, idx;
}task[maxn];

bool cmp_finish(query q1, query q2)
{
    return q1.finish < q2.finish;
}
int n, q;   


void input()
{
    cin >> n >> q;
    for (int i = 1; i <= n; i ++)
    {
        cin >> seg[i].s >> seg[i].e;
        seg[i].idx = i;
    }
    for (int i = 1; i <= q; i ++)
    {
        cin >> task[i].start >> task[i].finish;
        task[i].idx = i;
    }
}



bool cmp_end(interval seg1, interval seg2)
{
    return seg1.e < seg2.e;
}

int lf[maxn], rev[maxn], rf[maxn], ans[maxn];
map < int, int > fix;
void build_graph()
{
    sort(seg + 1, seg + n + 1, cmp_end);
    for (int i = 1; i <= n; i ++)
    {
        rev[seg[i].idx] = i;
    }

    for (int i = 1; i <= n; i ++)
    {
        int l = 1;
        int r = i;
        while(l <= r)
        {
            int m = (l + r) / 2;
            if (seg[m].e < seg[i].s)
                l = m + 1;
            else
                r = m - 1;
        }
        lf[i] = l;
        //while(seg[lf[i]].e < seg[i].s)
           // lf[i] ++;


        if (fix[seg[i].e] == 0)
            fix[seg[i].e] = lf[i];
        else
            fix[seg[i].e] = min(fix[seg[i].e], lf[i]);
    }
}

void answer_queries()
{
    for (int i = 1; i <= q; i ++)
    {
        task[i].start = rev[task[i].start];
        task[i].finish = rev[task[i].finish];
    }
    sort(task + 1, task + q + 1, cmp_finish);
    /**cout << "----------------------" << endl;
    for (int i = 1; i <= n; i ++)
        cout << seg[i].s << " :: " << seg[i].e << endl;*/
    vector < int > viable;
    for (int i = 1; i <= n; i ++)
    {

    }

    int pt = 1;
    for (int i = 1; i <= q; i ++)
    {

        int st = task[i].start, en = task[i].finish;

        while(pt <= en)
        {
            
            while(!viable.empty() && lf[viable.back()] >= lf[pt])
                viable.pop_back();
            viable.push_back(pt);
            pt ++;
        }
    if (st == en)
        {
            ans[task[i].idx] = 0;
            continue;
        }
        if (seg[st].e == seg[en].e && st != en)
        {
            ans[task[i].idx] = 1;
            continue;
        }
        
        if (st > en)
        {
            ans[task[i].idx] = -1;
            continue;
        }

        if (st >= lf[en])
        {
            ans[task[i].idx] = 1;
            continue;
        }

        
    
        int to = fix[seg[en].e];
        for (int i = lf[en]; i <= en; i ++)
            to = min(to, lf[i]);
        int steps = 1;

        bool done = false;
        int cur = viable.size() - 1;
        while(to > st)
        {
            while(cur >= 0 && viable[cur] >= to)
                cur --;
            cur ++;
            if (lf[viable[cur]] >= to)
            {
                done = true;
                break;
            }

            steps ++;
            to = lf[viable[cur]];
        }

        if (done == true)
        {
            ans[task[i].idx] = -1;
        }
        else
        {
           ans[task[i].idx] = steps + 1;
        }
    }

    for (int i = 1; i <= q; i ++)
    {
        if (ans[i] != - 1)
            cout << ans[i] << endl;
        else
            cout << "impossible" << endl;
    }
}
void solve()
{  
    input();
    build_graph();
    answer_queries();
}

int main()
{   
    ///speed();
    solve();

    return 0;
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2396 KB Output is correct
2 Execution timed out 1589 ms 9396 KB Time limit exceeded
3 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2552 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 2 ms 2396 KB Output is correct
4 Correct 1 ms 2396 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2392 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2552 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 2 ms 2396 KB Output is correct
4 Correct 1 ms 2396 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2392 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 0 ms 2396 KB Output is correct
11 Correct 0 ms 2396 KB Output is correct
12 Correct 2 ms 2904 KB Output is correct
13 Correct 1 ms 2396 KB Output is correct
14 Correct 1 ms 2396 KB Output is correct
15 Correct 1 ms 2396 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct
17 Correct 1 ms 2396 KB Output is correct
18 Correct 2 ms 2396 KB Output is correct
19 Correct 835 ms 3716 KB Output is correct
20 Correct 1355 ms 3968 KB Output is correct
21 Correct 387 ms 5744 KB Output is correct
22 Correct 163 ms 4948 KB Output is correct
23 Correct 186 ms 4952 KB Output is correct
24 Correct 162 ms 4960 KB Output is correct
25 Correct 545 ms 4692 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2552 KB Output is correct
2 Correct 1 ms 2396 KB Output is correct
3 Correct 2 ms 2396 KB Output is correct
4 Correct 1 ms 2396 KB Output is correct
5 Correct 1 ms 2396 KB Output is correct
6 Correct 1 ms 2396 KB Output is correct
7 Correct 1 ms 2392 KB Output is correct
8 Correct 1 ms 2396 KB Output is correct
9 Correct 1 ms 2396 KB Output is correct
10 Correct 0 ms 2396 KB Output is correct
11 Correct 0 ms 2396 KB Output is correct
12 Correct 2 ms 2396 KB Output is correct
13 Correct 1 ms 2396 KB Output is correct
14 Correct 1 ms 2396 KB Output is correct
15 Correct 2 ms 2396 KB Output is correct
16 Correct 1 ms 2396 KB Output is correct
17 Correct 1 ms 2396 KB Output is correct
18 Correct 1 ms 2396 KB Output is correct
19 Correct 112 ms 8780 KB Output is correct
20 Correct 75 ms 8912 KB Output is correct
21 Correct 88 ms 5776 KB Output is correct
22 Correct 108 ms 8956 KB Output is correct
23 Correct 89 ms 8276 KB Output is correct
24 Correct 98 ms 8912 KB Output is correct
25 Correct 45 ms 3540 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1566 ms 9312 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 2396 KB Output is correct
2 Execution timed out 1589 ms 9396 KB Time limit exceeded
3 Halted 0 ms 0 KB -