| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 584432 | Koosha_mv | Event Hopping (BOI22_events) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
#define dbgv(v) cout<<#v<<" = "; f(i,0,v.size()) cout<<v[i]<<" "; cout<<endl
#define dbga(a,x,y) cout<<#a<<" = "; f(i,x,y) cout<<a[i]<<" "; cout<<endl
#define erorp(x) cout<<#x<<"={"<<x.F<<" , "<<x.S<<"}"<<endl
#define eror(x) cout<<#x<<'='<<(x)<<endl
#define f_(i,a,b) for(int i=a;i>=b;i--)
#define f(i,a,b) for(int i=a;i<b;i++)
#define nb(x) __builtin_popcount(x)
#define all(v) v.begin(),v.end()
#define bit(n,k) (((n)>>(k))&1)
#define Add(x,y) x=(x+y)%mod
#define maxm(a,b) a=max(a,b)
#define minm(a,b) a=min(a,b)
#define lst(x) x[x.size()-1]
#define sz(x) int(x.size())
#define mp make_pair
#define ll long long
#define pb push_back
#define S second
#define F first
const int N=1e5+99,lg=20;
int n,q,s[N],t[N],par[lg][N];
int32_t main(){
ios:: sync_with_stdio(0), cin.tie(0), cout.tie(0);
cin>>n>>q;
f(i,1,n+1){
cin>>s[i]>>t[i];
par[0][i]=i;
}
f(i,1,n+1){
f(j,1,n+1){
if(s[i]<=t[j] && t[j]<=t[i] && s[j]<s[par[0][i]]){
par[0][i]=j;
}
}
}
f(i,1,n+1){
f(l,1,lg){
par[l][i]=par[l-1][par[l-1][i]];
}
}
while(q--){
int u,v;
cin>>u>>v;
if(u==v){
cout<<0<<'\n';
continue ;
}
if(s[v]<=t[u]){
if(t[u]<=t[v]){
cout<<1<<'\n';
}
else{
cout<<"impossible"<<'\n';
}
continue ;
}
int ans=1;
f_(l,lg-1,0){
if(t[u]<s[par[l][v]]){
ans+=(1<<l);
v=par[l][v];
}
}
/*int p=N;
while(t[u]<s[v] && p--){
if(par[0][v]==v) break ;
v=par[0][v];
ans++;
}*/
now=par[0][now],ans++;
if(s[v]<=t[u]){
cout<<ans<<'\n';
}
else{
cout<<"impossible"<<'\n';
}
}
}
/*
8 1
1 2
3 4
1 5
6 7
5 10
10 20
15 20
999999999 1000000000
1 6
*/