oj.uz

Submission #984553

# Submission time Handle Problem Language Result Execution time Memory
984553 2024-05-16T18:40:40 Z Ahmed57 Alternating Current (BOI18_alternating) C++17
19 / 100
 27 ms 10508 KB 
#include <bits/stdc++.h>

using namespace std;
#define int long long

signed main(){
    ios_base::sync_with_stdio(false);cin.tie(0);
    int n,m;cin>>n>>m;
    int pref[n+2] = {0};
    vector<array<int,3>> v;
    vector<array<int,2>> rng[n+1];
    int dir[m+1] = {0};
    int ma = -1, lol = -1;
    int mi = 1e9;
    for(int i = 0;i<m;i++){
        int a,b;cin>>a>>b;
        if(a<=b){
            pref[a]++;
            pref[b+1]--;
        }else{
            pref[a]++;
            pref[1]++;
            pref[b+1]--;
            b+=n;
        }
        v.push_back({a,b,i});
        rng[a].push_back({b,i});
        if(a<=mi){
            if(a<mi){
                mi = a;
                ma = -1;
            }
            if(b>ma){
                ma = b;
                lol = i;
            }
        }
    }    
    for(int i = 2;i<=n;i++){
        pref[i]+=pref[i-1];
    }
    for(int i = 1;i<=n;i++){
        if(pref[i]<=1){
            cout<<"impossible\n";
            return 0;
        }
    }
    for(int i = lol;i>=lol;i--){
        for(int j = 0;j<m;j++)dir[j] = 0;
        int ind = v[i][0];
        int nah = v[i][1], fe = v[i][2];
        bool bad = 0;
        while(ind<v[i][0]+n){
            if(ind-1==nah){
                bad = 1;
                break;
            }
            if(nah==-1){
                bad = 1;
                break;
            }
            int er = nah;
            dir[fe] = 1;
            if(er>=v[i][0]+n){
                break;
            }
            while(ind<=er){
                ind++;
                for(auto j:rng[(ind-1)%n+1]){
                    if(nah<(j[0]>n?j[0]:(ind<=n?j[0]:j[0]+n))){
                        nah = (j[0]>n?j[0]:(ind<=n?j[0]:j[0]+n));
                        fe = j[1];
                    }
                }
                if(ind<=er&&pref[(ind-1)%n+1]==2)nah = -1;
            }
        }
        int npref[n+2];
        for(int j = 1;j<=n;j++){
            npref[j] = 0;
        }
        for(int j = 0;j<m;j++){
            if(dir[j])continue;
            if(v[j][1]>n){
                npref[v[j][0]]++;
                npref[1]++;
                npref[(v[j][1]-1)%n+2]--;
            }else{
                npref[v[j][0]]++;
                npref[v[j][1]+1]--;
            }
        }
        for(int j = 2;j<=n;j++)npref[j]+=npref[j-1];
        for(int j = 1;j<=n;j++){
            if(npref[j]==0){
                bad = 1;
                break;
            }
        }
        if(bad==0){
            for(int j = 0;j<m;j++){
                cout<<dir[j];
            }
            return 0;
        }
    }
    cout<<"impossible\n";
}

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 1 ms 348 KB Output is correct
5 Incorrect 0 ms 348 KB 'impossible' claimed, but there is a solution
6 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 1 ms 348 KB Output is correct
5 Incorrect 0 ms 348 KB 'impossible' claimed, but there is a solution
6 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 1 ms 348 KB Output is correct
5 Incorrect 0 ms 348 KB 'impossible' claimed, but there is a solution
6 Halted 0 ms 0 KB -

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 9180 KB Output is correct
2 Correct 3 ms 4188 KB Output is correct
3 Correct 10 ms 6672 KB Output is correct
4 Correct 14 ms 7516 KB Output is correct
5 Correct 27 ms 10024 KB Output is correct
6 Correct 22 ms 9412 KB Output is correct
7 Correct 25 ms 10508 KB Output is correct
8 Correct 4 ms 4444 KB Output is correct
9 Correct 3 ms 4188 KB Output is correct
10 Correct 27 ms 10252 KB Output is correct
11 Correct 21 ms 10000 KB Output is correct
12 Correct 23 ms 10256 KB Output is correct
13 Correct 2 ms 3420 KB Output is correct
14 Correct 2 ms 3420 KB Output is correct
15 Correct 27 ms 10188 KB Output is correct
16 Correct 12 ms 6672 KB Output is correct
17 Correct 27 ms 10252 KB Output is correct
18 Correct 20 ms 6412 KB Output is correct
19 Correct 3 ms 3928 KB Output is correct
20 Correct 23 ms 8716 KB Output is correct

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 344 KB Output is correct
2 Correct 0 ms 344 KB Output is correct
3 Correct 0 ms 344 KB Output is correct
4 Correct 1 ms 348 KB Output is correct
5 Incorrect 0 ms 348 KB 'impossible' claimed, but there is a solution
6 Halted 0 ms 0 KB -