Submission #966420

#	Time	Username	Problem	Language	Result	Execution time	Memory
966420		ttamx	Cake 3 (JOI19_cake3)	C++17	0 / 100	2 ms	12892 KiB

cake3

#include<bits/stdc++.h>

using namespace std;

using ll = long long;
using t4=tuple<int,int,int,int>;

const int N=2e5+5;
const int K=1<<19;
const ll INF=LLONG_MAX/2;

int n,m;
ll v[N],c[N],pos[N];
ll ans=-INF;
pair<int,int> a[N];
vector<pair<int,int>> vec;
vector<t4> q;

struct Node{
    ll sum;
    int freq;
    Node():sum(0),freq(0){}
    Node(ll v):sum(v),freq(1){}
    Node(ll v,int f):sum(v),freq(f){}
    friend Node operator+(const Node &lhs,const Node &rhs){
        return Node(lhs.sum+rhs.sum,lhs.freq+rhs.freq);
    }
};

struct SegTree{
    Node t[K];
    void build(int l,int r,int i){
        t[i]=Node();
        if(l==r)return;
        int m=(l+r)/2;
        build(l,m,i*2);
        build(m+1,r,i*2+1);
    }
    void build(){
        build(1,n,1);
    }
    void update(int l,int r,int i,int x,const Node &v){
        if(x<l||r<x)return;
        if(l==r)return void(t[i]=v);
        int m=(l+r)/2;
        update(l,m,i*2,x,v);
        update(m+1,r,i*2+1,x,v);
        t[i]=t[i*2]+t[i*2+1];
    }
    void update(int x,const Node &v){
        update(1,n,1,x,v);
    }
    ll query(int l,int r,int i,int k){
        if(l==r)return t[i].sum;
        int m=(l+r)/2;
        if(t[i*2+1].freq<k)return query(l,m,i*2,k-t[i*2+1].freq)+t[i*2+1].sum;
        return query(m+1,r,i*2+1,k);
    }
    ll query(int k){
        return query(1,n,1,k);
    }
}s;

int st=1,ed=0;

void work(int l,int r){
    while(ed<r)s.update(pos[++ed],Node(v[ed]));
    while(st>l)s.update(pos[--st],Node(v[st]));
    while(ed>r)s.update(pos[ed--],Node());
    while(st<l)s.update(pos[st++],Node());
}

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n >> m;
    for(int i=1;i<=n;i++)cin >> a[i].second >> a[i].first;
    sort(a+1,a+n+1);
    for(int i=1;i<=n;i++){
        tie(c[i],v[i])=a[i];
        vec.emplace_back(v[i],i);
    }
    sort(vec.begin(),vec.end());
    for(int i=0;i<n;i++)pos[vec[i].second]=i+1;
    q.emplace_back(1,n-m+1,1,n);
    while(!q.empty()){
        vector<t4> nq;
        for(auto [l,r,optl,optr]:q){
            if(l>r)continue;
            int mid=(l+r)/2;
            ll res=-INF;
            int opt=-1;
            for(int i=max(mid+m-1,optl),cnt=0;i<=optr;i++){
                work(mid,i);
                ll tmp=s.query(m)-2*c[i];
                if(tmp>res)res=tmp,opt=i;
            }
            res+=2*c[mid];
            ans=max(ans,res);
            nq.emplace_back(l,mid-1,optl,opt);
            nq.emplace_back(mid+1,r,opt,optr);
        }
        swap(q,nq);
    }
    cout << ans;
}

Compilation message (stderr)

cake3.cpp: In function 'void work(int, int)':
cake3.cpp:67:29: warning: operation on 'ed' may be undefined [-Wsequence-point]
   67 |     while(ed<r)s.update(pos[++ed],Node(v[ed]));
      |                             ^~~~
cake3.cpp:68:29: warning: operation on 'st' may be undefined [-Wsequence-point]
   68 |     while(st>l)s.update(pos[--st],Node(v[st]));
      |                             ^~~~
cake3.cpp: In function 'int main()':
cake3.cpp:92:41: warning: unused variable 'cnt' [-Wunused-variable]
   92 |             for(int i=max(mid+m-1,optl),cnt=0;i<=optr;i++){
      |                                         ^~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 19
• Subtask 3: 0 / 76