Submission #1341049

#TimeUsernameProblemLanguageResultExecution timeMemory
1341049kokokai3단 점프 (JOI19_jumps)C++20
100 / 100
653 ms93160 KiB
#include<bits/stdc++.h>
using namespace std;
#define task "text"
#define fi first
#define se second
using ll = long long;
const int N = 5e5+5;
ll a[N],ans[N];
vector<pair<int,int>> query[N];
vector<int> conn[N];
int n,q;
struct segtree{
    ll maxa[4*N],st[4*N],lz[4*N];
    int n;
    void build(int id,int l,int r){
        if(l==r){
            maxa[id]=a[l];
            st[id]=a[l];
            return;
        }
        int mid=(l+r)>>1;
        build(id<<1,l,mid);
        build(id<<1|1,mid+1,r);
        maxa[id]=max(maxa[id<<1],maxa[id<<1|1]);
        st[id]=maxa[id];
    }
    void down(int id,int l,int r){
        if(lz[id] == 0) return;
        ll t=lz[id];
        lz[id<<1]=max(lz[id<<1],t);
        lz[id<<1|1]=max(lz[id<<1|1],t);
        st[id<<1]=max(st[id<<1],maxa[id<<1]+lz[id<<1]);
        st[id<<1|1]=max(st[id<<1|1],maxa[id<<1|1]+lz[id<<1|1]);
        lz[id]=0;
        return;
    }
    void update(int id,int l,int r,int u,int v,ll val){
        if(r<u || v<l) return;
        if(u<=l && r<=v){
            lz[id]=max(lz[id],val);
            st[id]=max(st[id],lz[id]+maxa[id]);
            return;
        }
        int mid=(l+r)>>1;
        down(id,l,r);
        update(id<<1,l,mid,u,v,val);
        update(id<<1|1,mid+1,r,u,v,val);
        st[id]=max({st[id],st[id<<1],st[id<<1|1]});
    }
    ll get(int id,int l,int r,int u,int v){
        if(r<u || v<l) return 0;
        if(u<=l && r<=v) return st[id];
        int mid=(l+r)>>1;
        down(id,l,r);
        return max(get(id<<1,l,mid,u,v),get(id<<1|1,mid+1,r,u,v));
    }
}st;
int main(){
    ios::sync_with_stdio(false);cin.tie(nullptr);cout.tie(nullptr);
    if(fopen(task".INP","r")){
        freopen(task".INP","r",stdin);
        //freopen(task".OUT","w",stdout);
    }
    cin>>n;
    for(int i=1;i<=n;i++) cin>>a[i];
    st.build(1,1,n);
    cin>>q;
    for(int i=1;i<=q;i++){
        int l,r;
        cin>>l>>r;
        query[l].push_back({r,i});
    }
    vector<int> stk;
    for(int i=1;i<=n;i++){
        while(!stk.empty() && a[stk.back()] < a[i]) stk.pop_back();
        if(!stk.empty()){
            conn[stk.back()].push_back(i);
        }
        stk.push_back(i);
    }
    stk.clear();
    for(int i=n;i>=1;i--){
        while(!stk.empty() && a[stk.back()] < a[i]) stk.pop_back();
        if(!stk.empty()){
            conn[i].push_back(stk.back());
        }
        stk.push_back(i);
    }
    stk.clear();
    for(int i=n;i>=1;i--){
        for(int j:conn[i]){
            int nxt=j+j-i;
            if(nxt <= n){
                st.update(1,1,n,nxt,n,a[i]+a[j]);
            }
        }
        for(auto &[r,id]:query[i]){
            ans[id]=st.get(1,1,n,i+2,r);
        }
    }
    for(int i=1;i<=q;i++){
        cout<<ans[i]<<'\n';
    }
}

Compilation message (stderr)

jumps.cpp: In function 'int main()':
jumps.cpp:61:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   61 |         freopen(task".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
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