oj.uz

Submission #721903

# Submission time Handle Problem Language Result Execution time Memory
721903 2023-04-11T08:40:59 Z MDSPro Event Hopping (BOI22_events) C++14
30 / 100
 151 ms 11916 KB 
#include "bits/stdc++.h"
 
using namespace std;

const int INF = 1e9;

int main(){
    cin.tie(0)->sync_with_stdio(0);
 
    int n,q; cin >> n >> q;
    vector<tuple<int,int,int>> ev;
    if(n <= 1000 && q <= 1000){
        for(int i = 0; i < n; ++i){
            int x,y; cin >> x >> y;
            ev.emplace_back(y,x,i+1);
        }

        sort(ev.begin(),ev.end());
    
        vector<int> nw_order(n+1);
        vector<int> left(n),right(n);
        for(int i = 0; i < n; ++i) {
            left[i] = get<1>(ev[i]);
            right[i] = get<0>(ev[i]);
            nw_order[get<2>(ev[i])] = i;
        }
        
        vector<vector<int>> g(n);
        for(int i = 0; i < n; ++i){
            for(int j = 0; j < n; ++j){
                if(i == j) continue;
                if(left[j] <= right[i] && right[i] <= right[j]) {
                    g[i].emplace_back(j);
                }
            }
        }

        auto get = [&](int a, int b){
            if(a == b) return 0;
            vector<int> dis(n,INF); dis[a] = 0;

            queue<int> q; q.push(a);
            while(!q.empty()){
                int mn = q.front(); q.pop();
                for(int z: g[mn]){
                    if(dis[z] == INF){
                        dis[z] = dis[mn]+1;
                        q.push(z);
                    }
                }
            }

            if(dis[b] == INF) return -1;
            else return dis[b];
        };

        while(q--){
            int a,b; cin >> a >> b;
            a = nw_order[a];
            b = nw_order[b];

            int dis = get(a,b);
            if(dis == -1) cout << "impossible\n";
            else cout << dis << '\n';
        }
    } else {
        for(int i = 0; i < n; ++i){
            int x,y; cin >> x >> y;
            ev.emplace_back(x,y,i+1);
        }

        sort(ev.begin(),ev.end());  
    
        vector<int> nw_order(n+1);
        vector<int> left(n),right(n);
        for(int i = 0; i < n; ++i) {
            left[i] = get<0>(ev[i]);
            right[i] = get<1>(ev[i]);
            nw_order[get<2>(ev[i])] = i;
        }
    
        vector<vector<int>> nxt(20,vector<int>(n+1));
        nxt[0][n] = n;
    
        int r = 0;
        for(int i = 0; i < n; ++i){
            while(r+1 < n && left[r+1] <= right[i]) r++;
    
            if(i != r) nxt[0][i] = r;
            else nxt[0][i] = n;
        }
        for(int i = 1; i < 20; ++i) {
            for(int j = 0; j <= n; ++j){
                nxt[i][j] = nxt[i-1][nxt[i-1][j]];
            }
        }
    
        auto get = [&](int x, int y){
            if(x == y) return 0;
            if(x > y) return -1;
            if(nxt[0][x] == n) return -1;
            if(nxt[0][x] > y) return 1;
    
            int cur = 0;
            for(int i = 19; i >= 0; --i){
                if(x == y) return cur;
                if(nxt[i][x] <= y) {
                    cur |= (1<<i);
                    x = nxt[i][x];
                }
            }
    
    
            if(x == y) return cur;
            if(nxt[0][x] == n) return -1;
            return cur+1;
        };
    
        while(q--){
            int a,b; cin >> a >> b;
            a = nw_order[a];
            b = nw_order[b];
    
            int ans = get(a,b);
            if(ans == -1) cout << "impossible\n";
            else cout << ans << '\n';
        }
    }
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 71 ms 11468 KB Output is correct
3 Correct 71 ms 11576 KB Output is correct
4 Correct 72 ms 11584 KB Output is correct
5 Incorrect 66 ms 11580 KB Output isn't correct
6 Halted 0 ms 0 KB -

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 5 ms 388 KB Output is correct
5 Correct 4 ms 340 KB Output is correct
6 Correct 9 ms 1108 KB Output is correct
7 Correct 22 ms 1992 KB Output is correct
8 Correct 23 ms 2900 KB Output is correct
9 Correct 151 ms 4428 KB Output is correct

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 5 ms 388 KB Output is correct
5 Correct 4 ms 340 KB Output is correct
6 Correct 9 ms 1108 KB Output is correct
7 Correct 22 ms 1992 KB Output is correct
8 Correct 23 ms 2900 KB Output is correct
9 Correct 151 ms 4428 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 5 ms 340 KB Output is correct
13 Correct 4 ms 340 KB Output is correct
14 Correct 4 ms 340 KB Output is correct
15 Correct 8 ms 1108 KB Output is correct
16 Correct 40 ms 1876 KB Output is correct
17 Correct 22 ms 3024 KB Output is correct
18 Correct 122 ms 4392 KB Output is correct
19 Correct 33 ms 1308 KB Output is correct
20 Correct 38 ms 1688 KB Output is correct
21 Incorrect 38 ms 1888 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 5 ms 340 KB Output is correct
4 Correct 5 ms 388 KB Output is correct
5 Correct 4 ms 340 KB Output is correct
6 Correct 9 ms 1108 KB Output is correct
7 Correct 22 ms 1992 KB Output is correct
8 Correct 23 ms 2900 KB Output is correct
9 Correct 151 ms 4428 KB Output is correct
10 Correct 1 ms 212 KB Output is correct
11 Correct 1 ms 212 KB Output is correct
12 Correct 6 ms 404 KB Output is correct
13 Correct 4 ms 340 KB Output is correct
14 Correct 5 ms 376 KB Output is correct
15 Correct 9 ms 1184 KB Output is correct
16 Correct 19 ms 1892 KB Output is correct
17 Correct 23 ms 2900 KB Output is correct
18 Correct 110 ms 4388 KB Output is correct
19 Correct 37 ms 10872 KB Output is correct
20 Incorrect 44 ms 11280 KB Output isn't correct
21 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 79 ms 11404 KB Output is correct
2 Correct 71 ms 11452 KB Output is correct
3 Correct 94 ms 11456 KB Output is correct
4 Correct 71 ms 11916 KB Output is correct
5 Correct 104 ms 11828 KB Output is correct
6 Correct 102 ms 11560 KB Output is correct
7 Correct 118 ms 11576 KB Output is correct
8 Correct 71 ms 11684 KB Output is correct
9 Correct 35 ms 10828 KB Output is correct
10 Correct 82 ms 11164 KB Output is correct
11 Correct 70 ms 10956 KB Output is correct
12 Correct 68 ms 11164 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 71 ms 11468 KB Output is correct
3 Correct 71 ms 11576 KB Output is correct
4 Correct 72 ms 11584 KB Output is correct
5 Incorrect 66 ms 11580 KB Output isn't correct
6 Halted 0 ms 0 KB -