Submission #1136679

#	Time	Username	Problem	Language	Result	Execution time	Memory
1136679		imarn	Event Hopping (BOI22_events)	C++20	30 / 100	95 ms	21056 KiB

events

#include<bits/stdc++.h>
#define ll long long
#define pii pair<int,int>
#define pll pair<ll,ll>
#define plx pair<ll,int>
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(),x.end()
#define vi vector<int>
#define vvi vector<vi>
#define pp pair<ll,int>
#define ub(x,i) upper_bound(all(x),i)-x.begin()
#define lb(x,i) lower_bound(all(x),i)-x.begin()
using namespace std;
const int mxn=2e5+5,inf=1e9+7;
int s[mxn],e[mxn];
int t[2*mxn]{0};
int up[mxn][20];
vector<pair<int,int>>vec;
vector<int>v,vv;
void upd(int i,int sz,int amt){
    i+=sz;t[i]=min(t[i],amt);
    for(i>>=1;i;i>>=1)t[i]=min(t[2*i],t[2*i+1]);
}
int qr(int l,int r,int sz,int rs=1e9){
    for(l+=sz,r+=sz;l<r;l>>=1,r>>=1){
        if(l&1)rs=min(rs,t[l++]);
        if(r&1)rs=min(rs,t[--r]);
    }return rs;
}
int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    int n,q;cin>>n>>q;
    for(int i=1;i<=n;i++)cin>>s[i]>>e[i],v.pb(s[i]),v.pb(e[i]);
    sort(all(v));v.erase(unique(all(v)),v.end());int m=v.size();
    for(int i=1;i<=n;i++)s[i]=lb(v,s[i]),e[i]=lb(v,e[i]),vec.pb({e[i],s[i]});
    sort(all(vec));for(int i=0;i<2*m;i++)t[i]=1e9;
    for(int i=0;i<m;i++)up[i][0]=mxn-1;
    for(auto [e,s] : vec){
        upd(e,m,e);
        up[e][0]=min(qr(s,e+1,m),up[e][0]);
    }
    for(int j=1;j<20;j++)for(int i=0;i<m;i++)up[i][j]=up[up[i][j-1]][j-1];
    while(q--){
        int x,y;cin>>x>>y;
        if(x==y){cout<<0<<'\n';continue;}
        if(s[y]<=e[x]&&e[x]<=e[y]){cout<<1<<'\n';continue;}
        if(e[x]>e[y]){cout<<"impossible\n";continue;}
        int rs=1;int cr=e[y];
        if(s[y]>up[cr][0])rs++;
        for(int i=19;i>=0;i--){
            if(up[cr][i]>e[x])rs+=(1<<i),cr=up[cr][i];
        }cr=up[cr][0];
        if(cr<=e[x])cout<<rs<<'\n';
        else cout<<"impossible\n";continue;
    }
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 10
• Subtask 3: 0 / 15
• Subtask 4: 0 / 15
• Subtask 5: 20 / 20
• Subtask 6: 0 / 30