BZOJ4209 : 西瓜王

#include<cstdio>
#include<algorithm>
using namespace std;
const int N=300010,M=6000000;
int n,m,i,x,y,k,a[N],b[N],tot,T[N],l[M],r[M],vc[M][2],c[2];long long v[M],sum,ans;
inline void read(int&a){char c;while(!(((c=getchar())>=‘0‘)&&(c<=‘9‘)));a=c-‘0‘;while(((c=getchar())>=‘0‘)&&(c<=‘9‘))(a*=10)+=c-‘0‘;}
inline int lower(int x){
  int l=1,r=n,mid,t;
  while(l<=r)if(b[mid=(l+r)>>1]<=x)l=(t=mid)+1;else r=mid-1;
  return t;
}
int ins(int x,int a,int b,int c,int d){
  int y=++tot;
  vc[y][0]=vc[x][0],vc[y][1]=vc[x][1];
  vc[y][d&1]++,v[y]=v[x]+d;
  if(a==b)return y;
  int mid=(a+b)>>1;
  if(c<=mid)l[y]=ins(l[x],a,mid,c,d),r[y]=r[x];else l[y]=l[x],r[y]=ins(r[x],mid+1,b,c,d);
  return y;
}
inline void ask(int x,int y,int k){
  int a=1,b=n,mid,t;
  c[0]=c[1]=sum=0;
  while(a<b){
    mid=(a+b)>>1,t=vc[r[x]][0]+vc[r[x]][1]-vc[r[y]][0]-vc[r[y]][1];
    if(k<=t)a=mid+1,x=r[x],y=r[y];
    else{
      k-=t;
      c[0]+=vc[r[x]][0]-vc[r[y]][0];
      c[1]+=vc[r[x]][1]-vc[r[y]][1];
      sum+=v[r[x]]-v[r[y]];
      b=mid,x=l[x],y=l[y];
    }
  }
  c[::b[a]&1]+=k,sum+=1LL*::b[a]*k;
}
inline int kth(int x,int y,int k,int p){
  int a=1,b=n,mid,t;
  while(a<b){
    mid=(a+b)>>1,t=vc[r[x]][p]-vc[r[y]][p];
    if(k<=t)a=mid+1,x=r[x],y=r[y];else k-=t,b=mid,x=l[x],y=l[y];
  }
  return ::b[a];
}
int main(){
  for(read(n),i=1;i<=n;i++)read(a[i]),b[i]=a[i];
  for(sort(b+1,b+n+1),i=1;i<=n;i++)T[i]=ins(T[i-1],1,n,lower(a[i]),a[i]);
  read(m);
  while(m--){
    read(x),read(y),read(k);
    if(k>y-x+1){puts("-1");continue;}
    ask(T[y],T[x-1],k);
    if(c[0]%2==0){printf("%lld\n",sum);continue;}
    for(ans=-1,i=0;i<2;i++)
      if(c[i]&&c[i^1]<vc[T[y]][i^1]-vc[T[x-1]][i^1])
        ans=max(ans,sum-kth(T[y],T[x-1],c[i],i)+kth(T[y],T[x-1],c[i^1]+1,i^1));
    printf("%lld\n",ans);
  }
  return 0;
}