Submission #1066737

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066737		12345678	Alternating Current (BOI18_alternating)	C++17	0 / 100	3044 ms	2512 KiB

alternating

#include <bits/stdc++.h>

using namespace std;

const int nx=1e5+5;

mt19937 rng(time(0));

int n, m, a[nx], b[nx], cur[nx], dp[nx], res[nx];
vector<pair<int, int>> v;

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>m;
    for (int i=0; i<m; i++) 
    {
        cin>>a[i]>>b[i];
        v.push_back({rng(), i});
        if (a[i]<=b[i]) for (int j=a[i]; j<=b[i]; j++) cur[j]++;
        else
        {
            for (int j=a[i]; j<=n; j++) cur[j]++;
            for (int j=1; j<=b[i]; j++) cur[j]++;
        }
    }
    sort(v.begin(), v.end());
    for (int i=0; i<m; i++)
    {
        int idx=v[i].second;
        int mn=INT_MAX;
        if (a[idx]<=b[idx]) for (int j=a[idx]; j<=b[idx]; j++) mn=min(mn, cur[j]);
        else
        {
            for (int j=a[idx]; j<=n; j++) mn=min(mn, cur[j]);
            for (int j=1; j<=b[idx]; j++) mn=min(mn, cur[j]);
        }
        if (mn>=2)
        {
            res[idx]=1;
            if (a[idx]<=b[idx]) for (int j=a[idx]; j<=b[idx]; j++) cur[j]--, dp[j]++;
            else
            {
                for (int j=a[idx]; j<=n; j++) cur[j]--, dp[j]++;
                for (int j=1; j<=b[idx]; j++) cur[j]--, dp[j]++;
            }
        }
    }
    for (int i=1; i<=n; i++) if (dp[i]==0) return cout<<"impossible", 0;
    for (int i=0; i<m; i++) cout<<res[i];
}

• Subtask 1: 0 / 13
• Subtask 2: 0 / 20
• Subtask 3: 0 / 22
• Subtask 4: 0 / 19
• Subtask 5: 0 / 26