【LOJ】apio2016烟火表演-可并堆&凸包

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讲解详见ppt%%%%

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代码

#include
#include
#include
#include
using namespace std;
typedef long long ll;
const int N=3e5+10;
const int M=2e6+10;
int n,m,cnt,d[N],f[N],rt[N];
ll len[N],sum;
struct P{;
  int lc,rc;ll dis,v;
}q[M];
char cc;
inline int rd()
{
    int x=0,f=1;
    while(!isdigit(cc=getchar())) if(cc=='-') f=-1;
    x=(cc^48);
    while(isdigit(cc=getchar())){x=x+(x<<2);x+=(x+(cc^48));}
    return x*f;
}

int merge(int x,int y)
{
    if(!x || !y) return x+y;
    if(q[x].v<q[y].v) swap(x,y);
    int &L=q[x].lc,&R=q[x].rc;
    R=merge(R,y);
    if(q[R].dis>q[L].dis) swap(L,R);
    q[x].dis= q[x].rc ? q[R].dis+1 : 0 ;
    return x;
}
inline void del(int &x){x=merge(q[x].lc,q[x].rc);}

int main(){
    n=rd();m=rd();
    for(int i=2;i<=n+m;i++){
        f[i]=rd();len[i]=rd();
        d[f[i]]++;sum+=len[i];
    }
    for(int i=n+m;i>1;i--){
        ll l=0,r=0;
        if(i<=n){
           while(--d[i]) del(rt[i]);
           r=q[rt[i]].v;del(rt[i]);
           l=q[rt[i]].v;del(rt[i]);
        }
        q[++cnt].v=l+len[i];q[++cnt].v=r+len[i];
        rt[i]=merge(rt[i],merge(cnt,cnt-1));
        rt[f[i]]=merge(rt[f[i]],rt[i]);
    }
    while(d[1]--) del(rt[1]);
    while(rt[1]) {sum-=q[rt[1]].v;del(rt[1]);}
    printf("%lld\n",sum);
}