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Submission #864281

# Submission time Handle Problem Language Result Execution time Memory
864281 2023-10-22T10:01:57 Z danikoynov Event Hopping (BOI22_events) C++14
50 / 100
 1500 ms 21792 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]);
    }
}

const int maxlog = 21;
int dp[maxlog][maxn];

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;

    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();
            
            int l = 0, r = (int)(viable.size()) - 1;
            while(l <= r)
            {
                int m = (l + r) / 2;
                if (viable[m] < lf[pt])
                    l = m + 1;
                else
                    r = m - 1;
            }
            if (l >= viable.size())
                dp[0][pt] = pt;
            else
                dp[0][pt] = viable[l];

            for (int j = 1; j < maxlog; j ++)
            {
                dp[j][pt] = dp[j - 1][dp[j - 1][pt]];
            }

            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(cur >= 0 && viable[cur] >= to)
            cur --;
        cur ++;

        if (st >= to)
        {
            ans[task[i].idx] = 2;
            continue;
        }
        if (lf[viable[cur]] >= to)
        {
            ans[task[i].idx] = -1;
                continue;
        }
        steps ++;
         
        int jump = 0, ver = viable[cur];
        if (st >= lf[ver])
        {
       
            ans[task[i].idx] = steps + 1;
            continue;
        }
        ///cout << "here " << task[i].idx << endl;
        for (int bit = maxlog - 1; bit >= 0; bit --)
        {
            if (lf[dp[bit][ver]] > st)
            {
                ver = dp[bit][ver];
                jump |= (1 << bit);
            }
        }

        jump ++;
        ver = dp[0][ver];
        
        if (st >= lf[ver])
        {
            ///cout << "HERE " << task[i].idx << endl;
            ans[task[i].idx] = steps + jump + 1;
        }
        else
        {
            ans[task[i].idx] = -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;
}

Compilation message

events.cpp: In function 'void answer_queries()':
events.cpp:117:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  117 |             if (l >= viable.size())
      |                 ~~^~~~~~~~~~~~~~~~
events.cpp:161:14: warning: unused variable 'done' [-Wunused-variable]
  161 |         bool done = false;
      |              ^~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 10584 KB Output is correct
2 Correct 260 ms 18364 KB Output is correct
3 Correct 267 ms 18384 KB Output is correct
4 Correct 272 ms 18124 KB Output is correct
5 Correct 266 ms 21128 KB Output is correct
6 Correct 263 ms 21456 KB Output is correct
7 Correct 268 ms 21500 KB Output is correct
8 Correct 267 ms 21784 KB Output is correct
9 Correct 259 ms 21716 KB Output is correct
10 Correct 272 ms 21792 KB Output is correct
11 Correct 263 ms 21716 KB Output is correct
12 Correct 219 ms 18516 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 10588 KB Output is correct
2 Correct 1 ms 10588 KB Output is correct
3 Correct 2 ms 10588 KB Output is correct
4 Correct 2 ms 10684 KB Output is correct
5 Correct 2 ms 10588 KB Output is correct
6 Correct 2 ms 10588 KB Output is correct
7 Correct 2 ms 10840 KB Output is correct
8 Correct 2 ms 10584 KB Output is correct
9 Correct 2 ms 10588 KB Output is correct

Subtask #3
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 10588 KB Output is correct
2 Correct 1 ms 10588 KB Output is correct
3 Correct 2 ms 10588 KB Output is correct
4 Correct 2 ms 10684 KB Output is correct
5 Correct 2 ms 10588 KB Output is correct
6 Correct 2 ms 10588 KB Output is correct
7 Correct 2 ms 10840 KB Output is correct
8 Correct 2 ms 10584 KB Output is correct
9 Correct 2 ms 10588 KB Output is correct
10 Correct 1 ms 10588 KB Output is correct
11 Correct 1 ms 10588 KB Output is correct
12 Correct 2 ms 10588 KB Output is correct
13 Correct 2 ms 10588 KB Output is correct
14 Correct 2 ms 10584 KB Output is correct
15 Correct 2 ms 10588 KB Output is correct
16 Correct 2 ms 10588 KB Output is correct
17 Correct 2 ms 10588 KB Output is correct
18 Correct 2 ms 10588 KB Output is correct
19 Correct 456 ms 11784 KB Output is correct
20 Correct 171 ms 11856 KB Output is correct
21 Correct 168 ms 12372 KB Output is correct
22 Correct 169 ms 12116 KB Output is correct
23 Correct 177 ms 12152 KB Output is correct
24 Correct 164 ms 12456 KB Output is correct
25 Correct 173 ms 11636 KB Output is correct

Subtask #4
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 10588 KB Output is correct
2 Correct 1 ms 10588 KB Output is correct
3 Correct 2 ms 10588 KB Output is correct
4 Correct 2 ms 10684 KB Output is correct
5 Correct 2 ms 10588 KB Output is correct
6 Correct 2 ms 10588 KB Output is correct
7 Correct 2 ms 10840 KB Output is correct
8 Correct 2 ms 10584 KB Output is correct
9 Correct 2 ms 10588 KB Output is correct
10 Correct 1 ms 10588 KB Output is correct
11 Correct 1 ms 10588 KB Output is correct
12 Correct 2 ms 10584 KB Output is correct
13 Correct 2 ms 10588 KB Output is correct
14 Correct 2 ms 10588 KB Output is correct
15 Correct 2 ms 10588 KB Output is correct
16 Correct 2 ms 10588 KB Output is correct
17 Correct 2 ms 10588 KB Output is correct
18 Correct 2 ms 10584 KB Output is correct
19 Correct 94 ms 17348 KB Output is correct
20 Correct 78 ms 17360 KB Output is correct
21 Correct 91 ms 14224 KB Output is correct
22 Correct 93 ms 17048 KB Output is correct
23 Correct 94 ms 16916 KB Output is correct
24 Correct 94 ms 17360 KB Output is correct
25 Correct 50 ms 11884 KB Output is correct

Subtask #5
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 257 ms 18384 KB Output is correct
2 Correct 270 ms 18376 KB Output is correct
3 Correct 273 ms 18552 KB Output is correct
4 Correct 274 ms 21772 KB Output is correct
5 Correct 264 ms 21452 KB Output is correct
6 Correct 274 ms 21248 KB Output is correct
7 Correct 308 ms 21304 KB Output is correct
8 Correct 294 ms 21204 KB Output is correct
9 Correct 91 ms 18512 KB Output is correct
10 Correct 308 ms 20944 KB Output is correct
11 Execution timed out 1556 ms 20692 KB Time limit exceeded
12 Halted 0 ms 0 KB -

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 10584 KB Output is correct
2 Correct 260 ms 18364 KB Output is correct
3 Correct 267 ms 18384 KB Output is correct
4 Correct 272 ms 18124 KB Output is correct
5 Correct 266 ms 21128 KB Output is correct
6 Correct 263 ms 21456 KB Output is correct
7 Correct 268 ms 21500 KB Output is correct
8 Correct 267 ms 21784 KB Output is correct
9 Correct 259 ms 21716 KB Output is correct
10 Correct 272 ms 21792 KB Output is correct
11 Correct 263 ms 21716 KB Output is correct
12 Correct 219 ms 18516 KB Output is correct
13 Correct 1 ms 10588 KB Output is correct
14 Correct 1 ms 10588 KB Output is correct
15 Correct 2 ms 10588 KB Output is correct
16 Correct 2 ms 10684 KB Output is correct
17 Correct 2 ms 10588 KB Output is correct
18 Correct 2 ms 10588 KB Output is correct
19 Correct 2 ms 10840 KB Output is correct
20 Correct 2 ms 10584 KB Output is correct
21 Correct 2 ms 10588 KB Output is correct
22 Correct 1 ms 10588 KB Output is correct
23 Correct 1 ms 10588 KB Output is correct
24 Correct 2 ms 10588 KB Output is correct
25 Correct 2 ms 10588 KB Output is correct
26 Correct 2 ms 10584 KB Output is correct
27 Correct 2 ms 10588 KB Output is correct
28 Correct 2 ms 10588 KB Output is correct
29 Correct 2 ms 10588 KB Output is correct
30 Correct 2 ms 10588 KB Output is correct
31 Correct 456 ms 11784 KB Output is correct
32 Correct 171 ms 11856 KB Output is correct
33 Correct 168 ms 12372 KB Output is correct
34 Correct 169 ms 12116 KB Output is correct
35 Correct 177 ms 12152 KB Output is correct
36 Correct 164 ms 12456 KB Output is correct
37 Correct 173 ms 11636 KB Output is correct
38 Correct 1 ms 10588 KB Output is correct
39 Correct 1 ms 10588 KB Output is correct
40 Correct 2 ms 10584 KB Output is correct
41 Correct 2 ms 10588 KB Output is correct
42 Correct 2 ms 10588 KB Output is correct
43 Correct 2 ms 10588 KB Output is correct
44 Correct 2 ms 10588 KB Output is correct
45 Correct 2 ms 10588 KB Output is correct
46 Correct 2 ms 10584 KB Output is correct
47 Correct 94 ms 17348 KB Output is correct
48 Correct 78 ms 17360 KB Output is correct
49 Correct 91 ms 14224 KB Output is correct
50 Correct 93 ms 17048 KB Output is correct
51 Correct 94 ms 16916 KB Output is correct
52 Correct 94 ms 17360 KB Output is correct
53 Correct 50 ms 11884 KB Output is correct
54 Correct 257 ms 18384 KB Output is correct
55 Correct 270 ms 18376 KB Output is correct
56 Correct 273 ms 18552 KB Output is correct
57 Correct 274 ms 21772 KB Output is correct
58 Correct 264 ms 21452 KB Output is correct
59 Correct 274 ms 21248 KB Output is correct
60 Correct 308 ms 21304 KB Output is correct
61 Correct 294 ms 21204 KB Output is correct
62 Correct 91 ms 18512 KB Output is correct
63 Correct 308 ms 20944 KB Output is correct
64 Execution timed out 1556 ms 20692 KB Time limit exceeded
65 Halted 0 ms 0 KB -