Submission #108038

#	Time	Username	Problem	Language	Result	Execution time	Memory
108038		dragonslayerit	Cake 3 (JOI19_cake3)	C++14	100 / 100	918 ms	17220 KiB

cake3

#include <cstdio>
#include <vector>
#include <algorithm>
#include <queue>
#include <cassert>
#include <set>
#include <stdint.h>
#include <map>

const int64_t INF=1e15+7;

std::vector<std::pair<int,int> > cake;

int cps[200005];

int N,M;

const int MAXN=1<<18;

struct Node{
  int cnt;
  int64_t sum;
  Node():cnt(0),sum(0){
  }
}st[MAXN*2];

void st_add(int i,int c,int64_t v){
  //printf("st_add(%d,%d,%ld)\n",i,c,v);
  for(i+=MAXN;i>0;i>>=1){
    st[i].cnt+=c;
    st[i].sum+=v;
  }
}
/*
void st_insert(int x,int c){
  //printf("st_insert(%d) x%d\n",x,c);
  assert(cps[x]>=0&&cps[x]<MAXN);
  st_add(cps[x],c,x*c);
}
*/
int64_t st_sum(int w,int L,int R,int k){
  assert(st[w].cnt>=k);
  if(k==0) return 0;
  if(st[w].cnt==k){
    return st[w].sum;
  }
  int M=(L+R)/2;
  if(st[w<<1|1].cnt>=k){
    return st_sum(w<<1|1,M,R,k);
  }else{
    return st_sum(w<<1,L,M,k-st[w<<1|1].cnt)+st[w<<1|1].sum;
  }
}

void st_dump();

int64_t st_sum(int k){
  /*
  int64_t sum=0,cnt=0;
  for(int i=MAXN-1;i>=0&&cnt<k;i--){
    sum+=st[i+MAXN].sum;
    cnt+=st[i+MAXN].cnt;
  }
  assert(cnt==k);
  */
  //st_dump();
  //printf("st_sum(%d)=%ld\n",k,sum);
  //return sum;

  //assert(sum==st_sum(1,0,MAXN,k));
  return st_sum(1,0,MAXN,k);
}

void st_dump(){
  for(int i=0;i<2*MAXN;i++){
    if(st[i].cnt) printf(" ST[%d](%d): %ld\n",i,st[i].cnt,st[i].sum);
  }
}

struct DataStruct{
  int ll,rr;//(ll,rr) for elements, [ll,rr] for query
  DataStruct():ll(0),rr(1){
  }
  void add(int i){
    st_add(cps[i],1,cake[i].second);
  }
  void rem(int i){
    st_add(cps[i],-1,-cake[i].second);
  }
  int64_t query(int l,int r){
    if(r-l+1<M) return -INF;
    while(ll>l) add(ll--);
    while(rr<r) add(rr++);
    while(ll<l) rem(++ll);
    while(rr>r) rem(--rr);
    return st_sum(M-2)+cake[l].second+cake[r].second+2LL*(cake[l].first-cake[r].first);
  }
}ds;

int64_t best=-INF;

//find ans for (l,r), which must be in range [low,high]
void solve(int l,int r,int low,int high){
  if(r-l<=1) return;
  int m=(l+r)/2;
  int64_t max=-INF;
  int maxi=-1;
  for(int i=low;i<=high;i++){
    int64_t res=ds.query(m,i);
    if(res>=max){
      maxi=i;
      max=res;
    }
  }
  best=std::max(best,max);
  //printf("best with l=%ld: %ld\n",m,max);
  solve(l,m,low,maxi);
  solve(m,r,maxi,high);
}

int64_t brute(int64_t l,int64_t r){
  if(r-l+1<M) return -INF;
  std::multiset<int> best;
  for(int64_t i=l+1;i<r;i++){
    best.insert(cake[i].second);
  }
  while(best.size()>M-2){
    best.erase(best.begin());
  }
  assert(best.size()==M-2);
  best.insert(cake[l].second);
  best.insert(cake[r].second);
  int64_t sum=2LL*(cake[l].first-cake[r].first);
  for(int64_t x:best){
    sum+=x;
  }
  return sum;
}

int main(){
  scanf("%d %d",&N,&M);
  std::vector<std::pair<int,int> > vs;
  for(int i=0;i<N;i++){
    int V,C;
    scanf("%d %d",&V,&C);
    cake.push_back({C,V});
  }
  std::sort(cake.begin(),cake.end());
  for(int i=0;i<N;i++){
    vs.push_back({cake[i].second,i});
  }
  std::sort(vs.begin(),vs.end());
  for(int i=0;i<N;i++){
    cps[vs[i].second]=i;
  }
  /*
    for(int l=0;l<N;l++){
    for(int r=0;r<N;r++){
      printf("%ld,%ld ",ds.query(l,r),brute(l,r));
      //assert(ds.query(l,r)==brute(l,r));
    }
    printf("\n");
    }
  */
  solve(-1,N,0,N-1);
  /*
  for(int l=0;l<N;l++){
    for(int r=l;r<N;r++){
      best=std::max(best,brute(l,r));
    }
  }
  */
  printf("%ld\n",best);
  //ds.query(0,N-1),ds.dump();
  return 0;
}

Compilation message (stderr)

cake3.cpp: In function 'int64_t brute(int64_t, int64_t)':
cake3.cpp:127:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(best.size()>M-2){
         ~~~~~~~~~~~^~~~
In file included from /usr/include/c++/7/cassert:44:0,
                 from cake3.cpp:5:
cake3.cpp:130:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   assert(best.size()==M-2);
          ~~~~~~~~~~~^~~~~
cake3.cpp: In function 'int main()':
cake3.cpp:141:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&N,&M);
   ~~~~~^~~~~~~~~~~~~~~
cake3.cpp:145:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d",&V,&C);
     ~~~~~^~~~~~~~~~~~~~~

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