Submission #959670

#	Time	Username	Problem	Language	Result	Execution time	Memory
959670		happy_node	Railway Trip 2 (JOI22_ho_t4)	C++17	100 / 100	1140 ms	116728 KiB

Main

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
 
const int MX=1e6+5, MK=20;
 
int N,K,M,Q;
 
int L[MX],R[MX], A[MX], B[MX];
 
struct segtree {
        pair<int,int> t[4 * MX];
        // I define t[v] to be the range within reach from v by using 2^k steps
 
        pair<int,int> merge(pair<int,int> a, pair<int, int> b) {
                int l=min(a.first,b.first);
                int r=max(a.second,b.second);
                return make_pair(l,r);
        }
 
        void update(int v, int l, int r, int pos, pair<int,int> val) {
                if(l > pos || r < pos) return;
                if(l == r) {
                        t[v] = val;
                        return;
                }
                int mid = (l + r) >> 1;
                update(v * 2 + 0, l, mid + 0, pos, val);
                update(v * 2 + 1, mid + 1, r, pos, val);
                t[v] = merge(t[v * 2 + 0], t[v * 2 + 1]);
        }
 
        pair<int,int> query(int v, int l, int r, int ql, int qr) {
                if(ql > r || qr < l) return make_pair(1e9,0);
                if(ql <= l && qr >= r) return t[v];
                int mid = (l + r) >> 1;
                return merge(query(v * 2 + 0, l, mid + 0, ql, qr), query(v * 2 + 1, mid + 1, r, ql, qr));
        }
 
        void reset() {
                for(int i=0;i<4*MX;i++)
                        t[i]=make_pair(1e9,0);
        }
} ST[MK];
 
vector<int> opens[MX], closes[MX];
 
int main() {
        cin.tie(0); ios_base::sync_with_stdio(0);

        cin>>N>>K>>M;
        for(int i=1;i<=M;i++) {
                cin>>A[i]>>B[i];
                if(A[i]<B[i]) {
                        opens[A[i]].push_back(B[i]);
                        closes[min(A[i]+K-1,B[i]-1)].push_back(B[i]);
                } 
        }
 
        multiset<int> st;
        for(int i=1;i<=N;i++) {
                for(auto j:opens[i]) {
                        st.insert(j);
                }
                if(st.size())
                        R[i]=*st.rbegin();
                else
                        R[i]=i;
                for(auto j:closes[i]) {
                        st.erase(st.find(j));
                }
        }
 
        for(int i=1;i<=N;i++) {
                opens[i].clear();
                closes[i].clear();
        }
 
        for(int i=1;i<=M;i++) {
                if(A[i]>B[i]) {
                        opens[A[i]].push_back(B[i]);
                        closes[max(A[i]-K+1,B[i]+1)].push_back(B[i]);
                }
        }
 
        st.clear();
        for(int i=N;i>=1;i--) {
                for(auto j:opens[i]) {
                        st.insert(j);
                }       
                if(st.size())
                        L[i]=*st.begin();
                else
                        L[i]=i;
                for(auto j:closes[i]) {
                        st.erase(st.find(j));
                }
        }
 
        for(int i=1;i<=N;i++) {
                ST[0].update(1,1,N,i,make_pair(L[i],R[i]));
        }
 
        for(int k=1;k<MK;k++) {
                for(int i=1;i<=N;i++) {
                        auto [l,r]=ST[k-1].query(1,1,N,i,i);
                        auto [nxtL,nxtR]=ST[k-1].query(1,1,N,l,r);
                        ST[k].update(1,1,N,i,make_pair(nxtL,nxtR));
                }
        }
 
        cin>>Q;
        for(int i=1;i<=Q;i++) {
                int s,t;
                cin>>s>>t;
 
                auto [l,r]=ST[MK-1].query(1,1,N,s,s);
 
                if(t<l||t>r) {
                        cout<<-1<<'\n';
                        continue;
                }

                int curL=s,curR=s,ans=0;
                for(int k=MK-1;k>=0;k--) {
                        int nxtL=ST[k].query(1,1,N,curL,curR).first;
                        int nxtR=ST[k].query(1,1,N,curL,curR).second;
 
                        assert(nxtL<=nxtR);
 
                        if(!(nxtL<=t&&t<=nxtR)) {
                                ans+=1<<k;
                                curL=nxtL;
                                curR=nxtR;
                        }
                }
 
                cout<<ans+1<<'\n';
        }
}

• Subtask 1: 8 / 8
• Subtask 2: 8 / 8
• Subtask 3: 11 / 11
• Subtask 4: 25 / 25
• Subtask 5: 35 / 35
• Subtask 6: 13 / 13