oj.uz

답안 #864198

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
864198 2023-10-22T08:33:13 Z danikoynov Event Hopping (BOI22_events) C++14
30 / 100
 1500 ms 44768 KB 
    #include<bits/stdc++.h>
    #define debug true
    #ifdef DEVAL 
        #define debug false
    #endif
     
    using namespace std;
     
    const int maxn = 1e5 + 10;
     
    struct interval
    {
        int s, e, idx;
    }seg[maxn];
     
    int n, q;   
    pair < int, int > task[maxn];
    void read()
    {
        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].first >> task[i].second;
        }
    }
     
     
    vector < int > adj[5010];
     
    int used[5010], dist[5010][5010];
    int my_queue[5010];
    void bfs(int start)
    {
        for (int i = 1; i <= n; i ++)
            used[i] = -1;
     
        used[start] = 0;
        int st = 1, en = 0;
        my_queue[++ en]  = start;
        while(st <= en)
        {
            int v = my_queue[st ++];
            for (int u : adj[v])
            {
                if (used[u] == - 1)
                {
                    used[u] = used[v] + 1;
                    my_queue[++ en] = u;
                }
            }
        }
    }
     
    void build_graph()
    {
        for (int i = 1; i <= n; i ++)
           for (int j = 1; j <= n; j ++)
            {
                if (seg[j].s <= seg[i].e && seg[i].e <= seg[j].e)
                    adj[i].push_back(j);
            }
    }
     
    void answer_queries()
    {
        for (int i = 1; i <= q; i ++)
        {
            if (dist[task[i].first][task[i].second] == -1)
                cout << "impossible" << endl;
            else
                cout << dist[task[i].first][task[i].second] << endl;
     
        }
    }
     
    void precalc()
    {
        for (int v = 1; v <= n; v ++)
        {
            bfs(v);
            for (int i = 1; i <= n; i ++)
                dist[v][i] = used[i];
        }
    }
     
    void speed()
    {
        ios_base::sync_with_stdio(false);
        cin.tie(NULL);
        cout.tie(NULL);
    }
    
    bool cmp(interval seg1, interval seg2)
    {
        return seg1.s < seg2.s;
    }

    const int maxlog = 21;

    int dp[maxlog][maxn], rev[maxn];
    void solve_no_intersect()
    {
        sort(seg + 1, seg + n + 1, cmp);
        int pt = n;
        for (int i = n; i > 0; i --)
        {
            while(seg[pt].s > seg[i].e)
                pt --;
            dp[0][i] = pt;
        }

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

        for (int i = 1; i <= n; i ++)
            rev[seg[i].idx] = i;
        for (int i = 1; i <= q; i ++)
        {
            int S = task[i].first, E = task[i].second;
            S = rev[S];
            E = rev[E];
            if (S > E)
            {
                cout << "impossible" << endl;
                continue;
            }

            if (S == E)
            {
                cout << 0 << endl;
                continue;
            }
        
            int jump = 0;
            for (int bit = maxlog - 1; bit >= 0; bit --)
            {
                if (dp[bit][S] < E)
                {
                    jump |= (1 << bit);
                    S = dp[bit][S];
                }
            }

            if (dp[0][S] < E)
                cout << "impossible" << endl;
            else
                cout << jump + 1 << endl;
        }

    }
    void solve()
    {
     
        read();
        if (n > 5000)
        {
            solve_no_intersect();
        }  
        else
        {
            build_graph();
      
            precalc();      if (n > 1000 || q > 100)
                exit(0);
            answer_queries(); 
        }       
    }
 
int main()
{
    speed();
    solve();
    return 0;
}
/**
3 2
1 2
2 3
3 4
1 3
2 3
 */

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 147 ms 13396 KB Output is correct
3 Correct 147 ms 13544 KB Output is correct
4 Correct 152 ms 13392 KB Output is correct
5 Incorrect 147 ms 13876 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 6488 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 12 ms 24924 KB Output is correct
4 Correct 10 ms 24924 KB Output is correct
5 Correct 13 ms 25084 KB Output is correct
6 Correct 62 ms 25684 KB Output is correct
7 Correct 142 ms 26448 KB Output is correct
8 Correct 174 ms 27728 KB Output is correct
9 Correct 966 ms 29072 KB Output is correct

Subtask #3
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 6488 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 12 ms 24924 KB Output is correct
4 Correct 10 ms 24924 KB Output is correct
5 Correct 13 ms 25084 KB Output is correct
6 Correct 62 ms 25684 KB Output is correct
7 Correct 142 ms 26448 KB Output is correct
8 Correct 174 ms 27728 KB Output is correct
9 Correct 966 ms 29072 KB Output is correct
10 Correct 1 ms 6488 KB Output is correct
11 Correct 1 ms 6488 KB Output is correct
12 Correct 12 ms 24924 KB Output is correct
13 Correct 10 ms 25092 KB Output is correct
14 Correct 13 ms 24920 KB Output is correct
15 Correct 47 ms 25868 KB Output is correct
16 Correct 140 ms 26668 KB Output is correct
17 Correct 171 ms 27764 KB Output is correct
18 Correct 951 ms 29068 KB Output is correct
19 Execution timed out 1534 ms 44768 KB Time limit exceeded
20 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 6488 KB Output is correct
2 Correct 1 ms 6492 KB Output is correct
3 Correct 12 ms 24924 KB Output is correct
4 Correct 10 ms 24924 KB Output is correct
5 Correct 13 ms 25084 KB Output is correct
6 Correct 62 ms 25684 KB Output is correct
7 Correct 142 ms 26448 KB Output is correct
8 Correct 174 ms 27728 KB Output is correct
9 Correct 966 ms 29072 KB Output is correct
10 Correct 1 ms 6492 KB Output is correct
11 Correct 1 ms 6492 KB Output is correct
12 Correct 12 ms 24924 KB Output is correct
13 Correct 10 ms 25124 KB Output is correct
14 Correct 12 ms 24924 KB Output is correct
15 Correct 46 ms 25680 KB Output is correct
16 Correct 142 ms 26452 KB Output is correct
17 Correct 227 ms 27932 KB Output is correct
18 Correct 946 ms 29332 KB Output is correct
19 Correct 25 ms 12892 KB Output is correct
20 Correct 23 ms 12788 KB Output is correct
21 Incorrect 26 ms 12892 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 165 ms 13396 KB Output is correct
2 Correct 174 ms 13396 KB Output is correct
3 Correct 149 ms 13392 KB Output is correct
4 Correct 147 ms 13904 KB Output is correct
5 Correct 160 ms 13852 KB Output is correct
6 Correct 153 ms 13648 KB Output is correct
7 Correct 155 ms 13652 KB Output is correct
8 Correct 158 ms 13752 KB Output is correct
9 Correct 25 ms 12888 KB Output is correct
10 Correct 144 ms 13200 KB Output is correct
11 Correct 148 ms 13016 KB Output is correct
12 Correct 154 ms 13256 KB Output is correct

Subtask #6
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 6492 KB Output is correct
2 Correct 147 ms 13396 KB Output is correct
3 Correct 147 ms 13544 KB Output is correct
4 Correct 152 ms 13392 KB Output is correct
5 Incorrect 147 ms 13876 KB Output isn't correct
6 Halted 0 ms 0 KB -