没啥可说的，树链剖分
代码
1 #include<cstdio> 2 #define N 1000010 3 int dp,pre[N],p[N],tt[N],size[N],f[N],gf[N]; 4 int l[N],r[N],go[N],v[N],s[N],tot,m; 5 int L[N],R[N],n,a,i; 6 char str[10]; 7 void link(int x,int y) 8 { 9 dp++;pre[dp]=p[x];p[x]=dp;tt[dp]=y; 10 } 11 void dfs1(int x,int fa) 12 { 13 int i=p[x]; 14 size[x]=1; 15 while (i) 16 { 17 dfs1(tt[i],x); 18 size[x]+=size[tt[i]]; 19 f[tt[i]]=x; 20 if (size[tt[i]]>size[go[x]]) go[x]=tt[i]; 21 i=pre[i]; 22 } 23 } 24 void dfs2(int x,int fa) 25 { 26 int i=p[x]; 27 L[x]=++tot; 28 gf[x]=fa; 29 if (go[x]) dfs2(go[x],fa); 30 while (i) 31 { 32 if (tt[i]!=go[x]) dfs2(tt[i],tt[i]); 33 i=pre[i]; 34 } 35 R[x]=tot; 36 } 37 void build(int x,int a,int b) 38 { 39 l[x]=a;r[x]=b; 40 if (b-a>1) 41 { 42 int m=(l[x]+r[x])>>1; 43 build(2*x,a,m); 44 build(2*x+1,m,b); 45 } 46 } 47 void clean(int x) 48 { 49 if (v[x]!=-1) 50 { 51 s[x]=(r[x]-l[x])*v[x]; 52 v[2*x]=v[x]; 53 v[2*x+1]=v[x]; 54 v[x]=-1; 55 } 56 } 57 void change(int x,int a,int b,int c) 58 { 59 clean(x); 60 if ((a<=l[x])&&(r[x]<=b)) 61 { 62 v[x]=c; 63 return; 64 } 65 int m=(l[x]+r[x])>>1; 66 if (a<m) change(2*x,a,b,c); 67 if (m<b) change(2*x+1,a,b,c); 68 clean(2*x);clean(2*x+1); 69 s[x]=s[2*x]+s[2*x+1]; 70 } 71 int query(int x,int a,int b) 72 { 73 clean(x); 74 if ((a<=l[x])&&(r[x]<=b)) 75 return s[x]; 76 int m=(l[x]+r[x])>>1,ans=0; 77 if (a<m) ans+=query(2*x,a,b); 78 if (m<b) ans+=query(2*x+1,a,b); 79 return ans; 80 } 81 int getans(int x) 82 { 83 int ans=0; 84 while (x) 85 { 86 // printf("%d %d ",L[gf[x]],L[x]); 87 ans=ans+(L[x]-L[gf[x]]+1)-query(1,L[gf[x]]-1,L[x]); 88 change(1,L[gf[x]]-1,L[x],1); 89 x=f[gf[x]]; 90 } 91 return ans; 92 } 93 int main() 94 { 95 scanf("%d",&n); 96 for (i=2;i<=n;i++) 97 { 98 scanf("%d",&a);a++; 99 link(a,i); 100 } 101 dfs1(1,0); 102 dfs2(1,1); 103 build(1,0,tot); 104 scanf("%d",&m); 105 for (i=1;i<=m;i++) 106 { 107 scanf("%s %d",str,&a);a++; 108 if (str[0]=='i') 109 printf("%d ",getans(a)); 110 else 111 { 112 // printf("%d %d ",L[a],R[a]); 113 printf("%d ",query(1,L[a]-1,R[a])); 114 change(1,L[a]-1,R[a],0); 115 } 116 } 117 }