【左偏树】[APIO2012]派遣

 1 #include<bits/stdc++.h>
 2 #define int long long
 3 #define writeln(x)  write(x),puts("")
 4 #define writep(x)   write(x),putchar(' ')
 5 using namespace std;
 6 inline int read(){
 7     int ans=0,f=1;char chr=getchar();
 8     while(!isdigit(chr)){if(chr=='-') f=-1;chr=getchar();}
 9     while(isdigit(chr)){ans=(ans<<3)+(ans<<1)+chr-48;chr=getchar();}
10     return ans*f;
11 }void write(int x){
12     if(x<0) putchar('-'),x=-x;
13     if(x>9) write(x/10);
14     putchar(x%10+'0');
15 }const int M = 2e5+5;
16 int n,m;
17 int son[M][2],fa[M],dis[M],val[M],a[M],b[M],ans;
18 int head[M],ver[M<<1],nxt[M<<1],tot,sum[M],sz[M];
19 #define ls son[x][0]
20 #define rs son[x][1]
21 inline void cmax(int &x,int y){if(x<y) x=y;}
22 inline void add(int x,int y){ver[++tot]=y,nxt[tot]=head[x],head[x]=tot;}
23 int Merge(int x,int y){
24     if(!x||!y) return x|y;
25     if(val[x]<val[y]) swap(x,y);
26     rs=Merge(rs,y);
27     if(dis[ls]<dis[rs]) swap(ls,rs);
28     fa[ls]=fa[rs]=fa[x]=x;
29     dis[x]=dis[rs]+1;
30     return x;
31 }
32 signed main(){
33     dis[0]=-1;
34     n=read(),m=read();
35     for(register long x,y,i=1;i<=n;++i)
36         fa[i]=i,sz[i]=1,x=read(),val[i]=sum[i]=read(),b[i]=read(),add(x,i);
37     for(register long x=n;x>=1;--x){
38         for(register long i=head[x];i;i=nxt[i]){
39             int y=ver[i];
40             fa[x]=fa[y]=Merge(fa[x],fa[y]);
41             sum[x]+=sum[y];
42             sz[x]+=sz[y] ;
43         }while(sum[x]>m){
44             sum[x]-=val[fa[x]];
45             --sz[x];
46             fa[x]=Merge(son[fa[x]][0],son[fa[x]][1]);
47         }cmax(ans,b[x]*sz[x]);
48     }printf("%lld",ans);
49     return 0;
50 }