bzoj2809

枚举管理者

则一定派遣子树中薪水最低的忍者，对于每个节点维护子树大根堆

若堆中忍者薪水和大于M，则pop

#include<cstdio>
#include<cctype>
#include<algorithm>
#define ll long long
using namespace std;
const int maxn=100002;
int cnt,n,m,root[maxn],c[maxn],ld[maxn],siz[maxn<<2],tr[maxn<<2][2],b[maxn],dis[maxn<<2],w[maxn<<2];
ll ans=-1,sum[maxn<<2];
inline void read(int &x){
    char ch=getchar();x=0;int f=1;
    while(!isdigit(ch)){if(ch=='-')f=-1;ch=getchar();}
    while(isdigit(ch)){x=(x<<1)+(x<<3)+ch-'0';ch=getchar();}
    x*=f;
}
inline int nownode(int x){
    sum[++cnt]=x;w[cnt]=x;siz[cnt]=1;return cnt;
}
inline int merge(int x,int y){
    if(!x || !y)return x+y;
    if(w[x]<w[y])swap(x,y);
    tr[x][1]=merge(tr[x][1],y);
    siz[x]=siz[tr[x][0]]+siz[tr[x][1]]+1;
    sum[x]=sum[tr[x][0]]+sum[tr[x][1]]+w[x];
    if(dis[tr[x][0]]<dis[tr[x][1]])swap(tr[x][0],tr[x][1]);
    dis[x]=dis[tr[x][1]]+1;
    return x;
}
int main(){
    read(n);read(m);
    for(int i=1;i<=n;i++){read(b[i]);read(c[i]);read(ld[i]);root[i]=nownode(c[i]);}
    for(int i=n;i>0;i--){
        while(sum[root[i]]>m)root[i]=merge(tr[root[i]][0],tr[root[i]][1]);
        ans=max(ans,1LL*ld[i]*siz[root[i]]);
        if(b[i])root[b[i]]=merge(root[i],root[b[i]]);
    }
    printf("%lld",ans);
    return 0;
}