oj.uz

Submission #536687

# Submission time Handle Problem Language Result Execution time Memory
536687 2022-03-13T21:05:07 Z OttoTheDino Alternating Current (BOI18_alternating) C++17
19 / 100
 68 ms 16212 KB 
#include <bits/stdc++.h>
using namespace std;

#define rep(i,s,e)                  for (int i = s; i <= e; ++i)
#define rrep(i,s,e)                 for (int i = s; i >= e; --i)
#define pb                          push_back
#define pf                          push_front
#define fi                          first
#define se                          second
#define all(a)                      a.begin(), a.end()
typedef long long ll;
typedef pair<int, int> ii;
typedef vector<ii> vii;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);

    int n, m; cin >>n >> m;
    vector<ii> v[2*n];
    set<ii> st;
    set<pair<ii,int>> s;

    rep (i,0,m-1) {
        int a, b; cin >> a >> b;
        a--, b--;
        if (b<a || a==0) {
            s.insert({{b,a},i});
        }
        else {
            v[a].pb({b,i});
        }
    }

    if (s.size()<2) {
        cout << "impossible\n";
        return 0;
    }

    int l = (*s.begin()).fi.fi, x = (*s.begin()).fi.se-1, idl = (*s.begin()).se;
    if (x==-1) x = n-1;
    s.erase(s.begin());
    int r = (*s.begin()).fi.fi, y = (*s.begin()).fi.se-1, idr = (*s.begin()).se;
    if (y==-1) y = n-1;
    s.erase(s.begin());

    if (y<x) {
        swap (l, r);
        swap (y, x);
        swap (idl, idr);
    }

    bool suc = 1, ans[m+1] = {};

    ans[idr] = 1;

    for (auto sth : s) {
        st.insert({sth.fi.fi, sth.se});
    }

    rep (i,0,n-1) {
        for (ii bi : v[i]) st.insert(bi);
        if (i>l && i<=x) {
            if (st.size()>1 && (*prev(st.end(),2)).fi>=i) {
                l = (*prev(st.end(),2)).fi;
                st.erase(prev(st.end(),2));
            }
            else if (st.size() && (*prev(st.end())).fi>=i) {
                l = (*prev(st.end())).fi;
                st.erase(prev(st.end()));
            }
            else {
                suc = 0;
                break;
            }
        }
        if (i>r && i<=y) {
            if (st.size() && (*st.rbegin()).fi>=i) {
                ans[(*st.rbegin()).se] = 1;
                r = (*st.rbegin()).fi;
                st.erase(--st.end());
            }
            else {
                suc = 0;
                break;
            }
        }
    }

    if (!suc) {
        cout << "impossible\n";
    }
    else {
        rep (i,0,m-1) cout << ans[i];
        cout << "\n";
    }

    return 0;
}

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Incorrect 1 ms 320 KB 'impossible' claimed, but there is a solution
4 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Incorrect 1 ms 320 KB 'impossible' claimed, but there is a solution
4 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Incorrect 1 ms 320 KB 'impossible' claimed, but there is a solution
4 Halted 0 ms 0 KB -

Subtask #4
19.0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 68 ms 16212 KB Output is correct
2 Correct 3 ms 4928 KB Output is correct
3 Correct 13 ms 6612 KB Output is correct
4 Correct 22 ms 9036 KB Output is correct
5 Correct 38 ms 7424 KB Output is correct
6 Correct 31 ms 8140 KB Output is correct
7 Correct 43 ms 7728 KB Output is correct
8 Correct 5 ms 5076 KB Output is correct
9 Correct 3 ms 4796 KB Output is correct
10 Correct 35 ms 7596 KB Output is correct
11 Correct 24 ms 7124 KB Output is correct
12 Correct 32 ms 8016 KB Output is correct
13 Correct 4 ms 4948 KB Output is correct
14 Correct 4 ms 4924 KB Output is correct
15 Correct 62 ms 9120 KB Output is correct
16 Correct 22 ms 8952 KB Output is correct
17 Correct 62 ms 11856 KB Output is correct
18 Correct 56 ms 6760 KB Output is correct
19 Correct 5 ms 5192 KB Output is correct
20 Correct 30 ms 4428 KB Output is correct

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 212 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Incorrect 1 ms 320 KB 'impossible' claimed, but there is a solution
4 Halted 0 ms 0 KB -