Submission #887462

#	Time	Username	Problem	Language	Result	Execution time	Memory
887462		cpptowin	Curtains (NOI23_curtains)	C++17	100 / 100	1044 ms	121008 KiB

curtains

#include<bits/stdc++.h>
#define fo(i,d,c) for(int i=d;i<=c;i++)
#define fod(i,c,d) for(int i=c;i>=d;i--)
#define maxn 1000010
#define N 1010
#define fi first
#define se second
#define pb emplace_back
#define en cout<<"\n";
#define int long long
#define inf 1000000000
#define pii pair<int,int>
#define vii vector<pii>
#define lb(x) x&-x
#define bit(i,j) ((i>>j)&1)
#define offbit(i,j) (i^(1<<j))
#define onbit(i,j) (i|(1<<j))
#define vi vector<int>
template <typename T1, typename T2> bool minimize(T1 &a, T2 b)
{
    if (a > b)
    {
        a = b;
        return true;
    }
    return false;
}
template <typename T1, typename T2> bool maximize(T1 &a, T2 b)
{
    if (a < b)
    {
        a = b;
        return true;
    }
    return false;
}
using namespace std;
vi ke[maxn];
pii query[maxn];
int firstl[maxn],firstr[maxn];
vii adj[maxn];
int ans[maxn];
int n;
void solve(int x,int y)
{
    if(x > y) return;
    fo(i,x,y) firstl[i] = inf,firstr[i] = -inf;
    int mid = (x + y) >> 1;
    stack<pii> st;
    fod(i,mid,x) if(ke[i].size())
    {
        int j = inf,k = -inf;
        for(int it : ke[i])
        {
            if(it < mid) k = max(k,it);
            if(it >= mid)
            {
                j = it;
                break;
            }
        }
        firstl[i] = min(firstl[i],j);
        while(st.size() and st.top().se <= k + 1)
        {
            firstl[i] = min(firstl[i],st.top().fi);
            st.pop();
        }
        st.push({firstl[i],i});
    }
    while(st.size()) st.pop();
    fo(i,min(mid,y),y) if(ke[i].size())
    {
        int j = -inf,k = inf;
        fod(u,(int)ke[i].size() - 1,0)
        {
            if(ke[i][u] > mid) k = min(k,ke[i][u]);
            if(ke[i][u] <= mid)
            {
                j = ke[i][u];
                break;
            }
        }
        firstr[i] = max(j,firstr[i]);
        while(st.size() and st.top().se >= k - 1)
        {
            firstr[i] = max(st.top().fi,firstr[i]);
            st.pop();
        }
        st.push({firstr[i],i});
    }
    fo(i,x,mid)
    {
        for(auto [u,id] : adj[i])
        {
            if(u > y) break;
            if(firstl[i] <= u and firstr[u] >= i) ans[id] = 1;
        }
    }
    if(x == y) return;
    solve(x,mid);
    solve(mid + 1,y);
}
int m,q;
main()
{
#define name "TASK"
    if(fopen(name".inp","r"))
    {
        freopen(name".inp","r",stdin);
        freopen(name".out","w",stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cin >> n >> m >> q;
    fo(i,1,m)
    {
        int u,v;
        cin >> u >> v;
        ke[u].pb(v);
        ke[v].pb(u);
    }
    fo(i,1,n) sort(ke[i].begin(),ke[i].end());
    fo(i,1,q)
    {
        int u,v;
        cin >> u >> v;
        adj[u].pb(v,i);
        adj[v].pb(u,i);
    }
    fo(i,1,n) sort(adj[i].begin(),adj[i].end());
    solve(1,n);
    fo(i,1,q) cout << (ans[i] ? "YES" : "NO") << "\n";
}

Compilation message (stderr)

curtains.cpp:104:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
  104 | main()
      | ^~~~
curtains.cpp: In function 'int main()':
curtains.cpp:109:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  109 |         freopen(name".inp","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
curtains.cpp:110:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  110 |         freopen(name".out","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 15 / 15
• Subtask 4: 20 / 20
• Subtask 5: 36 / 36
• Subtask 6: 20 / 20