oj.uz

Submission #604094

# Submission time Handle Problem Language Result Execution time Memory
604094 2022-07-24T17:50:54 Z Evirir Event Hopping (BOI22_events) C++17
20 / 100
 180 ms 20644 KB 
#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
//using namespace __gnu_pbds;

#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2")
#define watch(x) cout<<(#x)<<"="<<(x)<<'\n'
#define mset(d,val) memset(d,val,sizeof(d))
#define cbug if(DEBUG) cout
#define setp(x) cout<<fixed<<setprecision(x)
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define forn(i,a,b) for(int i=(a);i<(b);i++)
#define fore(i,a,b) for(int i=(a);i<=(b);i++)
#define pb push_back
#define F first
#define S second
#define fbo find_by_order
#define ook order_of_key
typedef long long ll;
typedef long double ld;
typedef pair<int,int> ii;
typedef vector<int> vi;
typedef vector<ii> vii;
//template<typename T>
//using pbds = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
void SD(int t=0){ cout<<"PASSED "<<t<<endl; }
ostream& operator<<(ostream &out, ii x){ out<<"("<<x.F<<","<<x.S<<")"; return out; }
template<typename T> void amax(T &a, T b){ a=max(a,b); }
template<typename T> void amin(T &a, T b){ a=min(a,b); }
const ll INF = ll(1e18);
const int MOD = 998244353;

class PointSegmentTree{
private:
	int size_;
	vector<ii> v;
	void update(int p, ii val, int k, int l, int r)
	{
		if(p < l || r < p) return;
		if(l == r){
			v[k]=val;	//modification
			return;
		}
		int mid = (l+r)>>1;
		update(p, val, k*2, l, mid);
		update(p, val, k*2+1, mid+1, r);
		v[k] = merge(v[k*2], v[k*2+1]);
	}
	ii query(int s, int e, int k, int l, int r)
	{
		if(e < l || r < s) return {-1,-1}; //dummy value
		if(s <= l && r <= e) return v[k];
		int mid = (l+r)>>1;
		ii lc = query(s, e, k*2, l, mid);
		ii rc = query(s, e, k*2+1, mid+1, r);
		return merge(lc, rc);
	}
	
public:
	PointSegmentTree(): v(vector<ii>()) {}
	PointSegmentTree(int n){
		for(size_=1;size_<n;) size_<<=1;
		v.resize(size_*4,{-1,-1});
	}
	//void reset(){}
	inline ii merge(ii x, ii y){
		return max(x,y);
	}
	inline void update(int p, ii val){
		update(p, val, 1, 0, size_-1);
	}
	inline ii query(int l, int r){
		return query(l, r, 1, 0, size_-1);
	}
};

const bool DEBUG = 0;
const int MAXN = 100005;
const int MAXA = MAXN * 2;
const int LG = 20;

int n,Q;
int s[MAXN], e[MAXN];  //reversed
ii mx[MAXA];
int nxt[MAXN][LG];
PointSegmentTree st;

vi comp;
int getid(int x){ return sz(comp) - 1 - (lower_bound(all(comp), x) - comp.begin()); }

int main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	mset(nxt,-1);

	cin>>n>>Q;
	forn(i,0,n)
	{
		cin>>e[i]>>s[i];
		comp.pb(s[i]);
		comp.pb(e[i]);
	}

	// compress everything in reverse
	sort(all(comp));
	forn(i,0,n)
	{
		s[i]=getid(s[i]);
		e[i]=getid(e[i]);
	}
	
	// compute first next
	forn(i,0,MAXA) mx[i]={-1,-1};
	forn(i,0,n) amax(mx[s[i]], {e[i], i});

	st=PointSegmentTree(MAXA);
	forn(i,0,MAXA) st.update(i, mx[i]);
	forn(i,0,n)
	{
		nxt[i][0] = st.query(s[i], e[i]).S;
	}

	// binary lifting
	forn(j,1,LG) forn(i,0,n) if(nxt[i][j-1]!=-1) nxt[i][j] = nxt[nxt[i][j-1]][j-1];

	forn(z,0,Q)
	{
		int u,v; cin>>v>>u; u--; v--;
		if(u==v)
		{
			cout<<0<<'\n';
			continue;
		}
		if(s[v]<s[u])
		{
			cout<<"impossible\n";
			continue;
		}
		if(s[v]<=e[u] && e[u]<=e[v])
		{
			cout<<1<<'\n';
			continue;
		}

		int ans=2;
		for(int j=LG-1;j>=0;j--)
		{
			// cout<<"u="<<u<<" j="<<j<<" nxt="<<nxt[u][j]<<'\n';
			if(nxt[u][j]!=-1 && e[nxt[u][j]]<s[v])
			{
				u=nxt[u][j];
				ans+=(1<<j);
				// cout<<"ans="<<ans<<'\n';
			}
		}
		u=nxt[u][0];
		assert(u!=-1);
		
		if(e[u]>=s[v]) cout<<ans<<'\n';
		else cout<<"impossible\n";
	}
	
	return 0;
}

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 17876 KB Output is correct
2 Correct 145 ms 20132 KB Output is correct
3 Correct 144 ms 20164 KB Output is correct
4 Correct 180 ms 20164 KB Output is correct
5 Correct 152 ms 20272 KB Output is correct
6 Correct 142 ms 20256 KB Output is correct
7 Correct 148 ms 20264 KB Output is correct
8 Incorrect 131 ms 20628 KB Output isn't correct
9 Halted 0 ms 0 KB -

Subtask #2
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 17876 KB Output is correct
2 Correct 39 ms 17856 KB Output is correct
3 Correct 44 ms 17856 KB Output is correct
4 Correct 37 ms 17876 KB Output is correct
5 Correct 36 ms 17896 KB Output is correct
6 Incorrect 37 ms 17880 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #3
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 17876 KB Output is correct
2 Correct 39 ms 17856 KB Output is correct
3 Correct 44 ms 17856 KB Output is correct
4 Correct 37 ms 17876 KB Output is correct
5 Correct 36 ms 17896 KB Output is correct
6 Incorrect 37 ms 17880 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #4
0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 38 ms 17876 KB Output is correct
2 Correct 39 ms 17856 KB Output is correct
3 Correct 44 ms 17856 KB Output is correct
4 Correct 37 ms 17876 KB Output is correct
5 Correct 36 ms 17896 KB Output is correct
6 Incorrect 37 ms 17880 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #5
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 138 ms 20192 KB Output is correct
2 Correct 173 ms 20136 KB Output is correct
3 Correct 171 ms 20136 KB Output is correct
4 Correct 145 ms 20644 KB Output is correct
5 Correct 178 ms 20540 KB Output is correct
6 Correct 161 ms 20428 KB Output is correct
7 Correct 156 ms 20340 KB Output is correct
8 Correct 175 ms 20464 KB Output is correct
9 Correct 138 ms 19724 KB Output is correct
10 Correct 151 ms 19944 KB Output is correct
11 Correct 150 ms 19904 KB Output is correct
12 Correct 159 ms 19960 KB Output is correct

Subtask #6
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 17876 KB Output is correct
2 Correct 145 ms 20132 KB Output is correct
3 Correct 144 ms 20164 KB Output is correct
4 Correct 180 ms 20164 KB Output is correct
5 Correct 152 ms 20272 KB Output is correct
6 Correct 142 ms 20256 KB Output is correct
7 Correct 148 ms 20264 KB Output is correct
8 Incorrect 131 ms 20628 KB Output isn't correct
9 Halted 0 ms 0 KB -