Submission #788599

#	Time	Username	Problem	Language	Result	Execution time	Memory
788599		Ahmed57	Cake 3 (JOI19_cake3)	C++17	100 / 100	1281 ms	21632 KiB

cake3

#include <bits/stdc++.h>

using namespace std;
#define int long long
vector<long long> pref;
long long cl = 0 ,cr = -1 , sz;
struct node{
    long long cnt = 0 , sum =0;
    node():cnt(0),sum(0){};
}seg[800001];
void build(int p,int l,int r){
    if(l==r){
        seg[p].cnt = 0;seg[p].sum = 0;
        return ;
    }
    int md = (l+r)/2;
    build(p*2,l,md);build(p*2+1,md+1,r);
    seg[p].cnt = seg[p*2].cnt+seg[p*2+1].cnt;
    seg[p].sum = seg[p*2].sum+seg[p*2+1].sum;
}
void update(int p,int l,int r,int idx,long long val){
    if(l==r){
        seg[p].cnt+=val;
        seg[p].sum+=val*pref[l-1];
        return ;
    }
    int md = (l+r)/2;
    if(idx<=md)update(p*2,l,md,idx,val);
    else update(p*2+1,md+1,r,idx,val);
    seg[p].cnt = seg[p*2].cnt+seg[p*2+1].cnt;
    seg[p].sum = seg[p*2].sum+seg[p*2+1].sum;
}
long long query(int p,int l,int r,long long idx){
    if(l==r){
        return pref[l-1]*idx;
    }
    int md = (l+r)/2;
    if(seg[p*2+1].cnt<idx)return seg[p*2+1].sum+query(p*2,l,md,idx-seg[p*2+1].cnt);
    return query(p*2+1,md+1,r,idx);
}
int k;
long long inf = 1e18;
signed main() {
    ios_base::sync_with_stdio(0);cin.tie(0);
    long long n;
    cin>>n>>k;
    vector<pair<long long,long long>> v;
    for(int i = 0;i<n;i++){
        long long a,b;
        cin>>a>>b;
        pref.push_back(a);
        v.push_back({b,a});
    }
    sort(pref.begin(),pref.end());
    pref.erase(unique(pref.begin(),pref.end()),pref.end());
    sz = pref.size();sort(v.begin(),v.end());
    for(int i = 0;i<n;i++){
        v[i].second = lower_bound(pref.begin(),pref.end(),v[i].second)-pref.begin()+1;
    }
    build(1,1,sz);
    auto cost = [&](int l,int r){
        while(cl>l)update(1,1,sz,v[--cl].second,1);
        while(cr<r)update(1,1,sz,v[++cr].second,1);
        while(cl<l)update(1,1,sz,v[cl++].second,-1);
        while(cr>r)update(1,1,sz,v[cr--].second,-1);
        return query(1,1,sz,k)-2*(v[r].first-v[l].first);
    };
    int ans = -inf;
    function<void(int,int,int,int)> dnc = [&](int l,int r,int optl,int optr){
        if(l>r) return;
        int sum=0,mid=(l+r)>>1;
        pair<int,int> opt={-inf,-1};
        for(int i=min(optr,mid-k+1);i>=optl;i--){
            int res=cost(i,mid);ans=max(ans,res);
            opt=max(opt,{res,i});
        }
        dnc(l,mid-1,optl,opt.second);
        dnc(mid+1,r,opt.second,optr);
    };
    dnc(k-1,n-1,0,n-k);
    cout<<ans<<endl;
    return 0;
}

Compilation message (stderr)

cake3.cpp: In lambda function:
cake3.cpp:71:13: warning: unused variable 'sum' [-Wunused-variable]
   71 |         int sum=0,mid=(l+r)>>1;
      |             ^~~

• Subtask 1: 5 / 5
• Subtask 2: 19 / 19
• Subtask 3: 76 / 76