Submission #1062336

#	Time	Username	Problem	Language	Result	Execution time	Memory
1062336		12345678	Port Facility (JOI17_port_facility)	C++17	0 / 100	1 ms	604 KiB

port_facility

#include <bits/stdc++.h>

using namespace std;

const int nx=2e3+5, mod=1e9+7;

int n, l[nx], r[nx], res=1, cnt, c[nx], f, vs[nx], f2;
vector<int> d[nx];
pair<int, int> v[2*nx];
stack<int> a, b;

void dfs(int u)
{
    vs[u]=1;
    for (auto v:d[u])
    {
        if (vs[v])
        {
            if (c[v]==c[u]) f=1;
            continue;
        }
        c[v]=!c[u];
        dfs(v);
    }
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n;
    for (int i=1; i<=n; i++) cin>>l[i]>>r[i], v[l[i]]={i, 1}, v[r[i]]={i, 0};
    for (int i=1; i<=2*n; i++)
    {
        if (v[i].second)
        {
            if (a.empty()&&b.empty()) a.push(v[i].first);
            else if (b.empty()) 
            {
                if (r[a.top()]>r[v[i].first]) a.push(v[i].first);
                else b.push(v[i].first);
            }
            else if (a.empty())
            {
                if (r[b.top()]>r[v[i].first]) b.push(v[i].first);
                else a.push(v[i].first);
            }
            else
            {
                if (max(r[a.top()], r[b.top()])<r[v[i].first])
                {
                    f2=1;
                    break;
                }
                if (r[a.top()]<r[b.top()])
                {
                    if (r[a.top()]>r[v[i].first]) a.push(v[i].first);
                    else b.push(v[i].first);
                }
                else
                {
                    if (r[b.top()]>r[v[i].first]) b.push(v[i].first);
                    else a.push(v[i].first);
                }
            }
        }
        else
        {
            if (!a.empty()&&a.top()==v[i].first) a.pop();
            else 
            {
                if (b.top()!=v[i].first) cout<<1/0;
                b.pop();
            }
        }
    }
    for (int i=1; i<=n; i++)
    {
        for (int j=i+1; j<=n; j++)
        {
            if ((l[i]<l[j]&&r[j]<r[i])||(l[j]<l[i]&&r[i]<r[j])||r[i]<l[j]||r[j]<l[i]) continue;
            d[i].push_back(j);
            d[j].push_back(i);
        }
    }
    for (int i=1; i<=n; i++) if (!vs[i]) dfs(i), res=(res*2)%mod;
    if (!f&&f2) cout<<1/0;
    if (f) cout<<1/0;
    cout<<res;
}

Compilation message (stderr)

port_facility.cpp: In function 'int main()':
port_facility.cpp:71:49: warning: division by zero [-Wdiv-by-zero]
   71 |                 if (b.top()!=v[i].first) cout<<1/0;
      |                                                ~^~
port_facility.cpp:86:24: warning: division by zero [-Wdiv-by-zero]
   86 |     if (!f&&f2) cout<<1/0;
      |                       ~^~
port_facility.cpp:87:19: warning: division by zero [-Wdiv-by-zero]
   87 |     if (f) cout<<1/0;
      |                  ~^~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 56
• Subtask 4: 0 / 22