Codeforces 384E-线段树+dfs序

如果这题只传到儿子不继续向下就是裸的dfs序+线段树，继续往下传的还改变正负号，我们可以根据它的层数来确定正负号

 #include<bits/stdc++.h>

 #define inf 0x3f3f3f3f

 #define lson (id<<1)

 #define rson ((id<<1)|1)

 #define mid ((l+r)>>1)

 const int maxn=;

 using namespace std;

 int t;

 int p;

 int n,m;

 int u,v;

 int x,val;

 int dep[maxn+];

 int a[maxn+];

 int pos[maxn+];

 int q[maxn+];

 int son[maxn+];

 int tree[maxn*+];

 int sum[maxn*+];

 int lazy[maxn*+];

 vector<int> G[maxn+];

 void push_up(int id){
    tree[id]=tree[lson]+tree[rson];
 }

 void push_down(int id,int l,int r){
         if(lazy[id]){
                 lazy[lson]+=lazy[id];
                 lazy[rson]+=lazy[id];
                 tree[lson]+=(mid-l+)*lazy[id];
                 tree[rson]+=(r-mid)*lazy[id];
                 lazy[id]=;
         }
         return ;
 }

 void build(int id,int l,int r){
       if(l==r){
         sum[id]=a[pos[l]];
         return ;
       }
       build(lson,l,mid);
       build(rson,mid+,r);
       push_up(id);
       return ;
 }

 void update(int id,int l,int r,int x,int y,int val){
         if(l==x&&r==y){
                 tree[id]+=val*(r-l+);
                 lazy[id]+=val;
                 return ;
         }
         push_down(id,l,r);
         if(x>mid){
                 update(rson,mid+,r,x,y,val);
         } else if(y<=mid){
                 update(lson,l,mid,x,y,val);
         } else {
                 update(lson,l,mid,x,mid,val);
                 update(rson,mid+,r,mid+,y,val);
         }
 }

 int fi(int id,int l,int r,int x){
         if(l==r){
                 int temp=dep[pos[l]]&;
                 if(!temp) temp=-;
                 return sum[id]+lazy[id]*temp;
         }
         push_down(id,l,r);
         if(x<=mid){
                 return fi(lson,l,mid,x);
         } else {
                 return fi(rson,mid+,r,x);
         }
 }

 void dfs(int x,int fa,int d){
         dep[x]=d;
         pos[++p]=x;
         q[x]=p;
         for(size_t i=;i<G[x].size();i++){
                 if(G[x][i]==fa) continue;
                 dfs(G[x][i],x,d+);
                 son[x]++;
                 son[x]+=son[G[x][i]];
         }
 }

 int main()
 {
     scanf("%d%d",&n,&m);
     for(int i=;i<=n;i++){
         scanf("%d",&a[i]);
     }
     for(int i=;i<n;i++){
         scanf("%d%d",&u,&v);
         G[u].push_back(v);
         G[v].push_back(u);
     }
     dfs(,,);
     build(,,n);
     for(int i=;i<=m;i++){
         scanf("%d",&t);
         if(t==){
         scanf("%d%d",&x,&val);
         if(dep[x]&)
         update(,,n,q[x],q[x]+son[x],val);
         else update(,,n,q[x],q[x]+son[x],-val);
         } else {
         scanf("%d",&x);
         int ans=fi(,,n,q[x]);
         printf("%d\n",ans);
         }
     }
     return ;
 }