BZOJ1036 树的统计Count

树链剖分模板题

#include<cstdio>
#include<algorithm>
using namespace std;
const int maxn = 3e4 + 5;
struct node{ int l, r, maxx, sum; } tree[maxn*4] ;
int ver[maxn*2], Next[maxn*2], head[maxn], num[maxn];
int fa[maxn], son[maxn], siz[maxn], top[maxn], dep[maxn], seg[maxn], rev[maxn];
char s[20];
int tot, maxx, sum;
inline int read()
{
    int s = 0, sign = 1; char ch = getchar();
    while(ch < '0' || ch > '9'){
        if(ch == '-') sign = -1;
        ch = getchar();
    }
    while(ch >= '0' && ch <= '9'){s = s*10+ch-'0'; ch = getchar(); }
    return s*sign;
}
void Add(int x,int y)
{
    ver[++tot] = y; Next[tot] = head[x]; head[x] = tot;
}
void dfs1(int u,int f)
{
    siz[u] = 1;
    fa[u] = f;
    dep[u] = dep[f]+1;
    for(int i = head[u]; i; i = Next[i]){
        int v = ver[i];
        if(v == f) continue;
        dfs1(v,u);
        siz[u] += siz[v];
        if(siz[v] > siz[son[u]]) son[u] = v;
    }
}
void dfs2(int u,int f)
{
    if(son[u]){
        seg[son[u]] = ++seg[0];
        top[son[u]] = top[u];
        rev[seg[0]] = son[u];
        dfs2(son[u],u);
    }
    for(int i = head[u]; i; i = Next[i]){
        int v = ver[i];
        if(top[v]) continue;
        seg[v] = ++seg[0];
        top[v] = v;
        rev[seg[0]] = v;
        dfs2(v,u);
    }
}
void build(int k,int l,int r)
{
    tree[k].l = l; tree[k].r = r;
    if(l == r){
        tree[k].maxx = num[rev[l]];
        tree[k].sum = num[rev[l]];
        return ;
    }
    int mid = (l+r)>>1;
    build(k<<1,l,mid);
    build(k<<1|1,mid+1,r);
    tree[k].maxx = max(tree[k<<1].maxx,tree[k<<1|1].maxx);
    tree[k].sum = tree[k<<1].sum+tree[k<<1|1].sum;
}
void update(int k,int p,int v)
{
    if(tree[k].l == tree[k].r && tree[k].l == p){
        tree[k].maxx = v; tree[k].sum = v;
        return ;
    }
    int mid = (tree[k].l+tree[k].r)/2;
    if(mid >= p) update(k<<1,p,v);
    else update(k<<1|1,p,v);
    tree[k].maxx = max(tree[k<<1].maxx,tree[k<<1|1].maxx);
    tree[k].sum = tree[k<<1].sum+tree[k<<1|1].sum;
}
void query(int k,int l,int r)
{
    if(tree[k].l > r || tree[k].r < l) return ;
    if(tree[k].l >= l && tree[k].r <= r){
        maxx = max(maxx,tree[k].maxx);
        sum += tree[k].sum;
        return ;
    }
    query(k<<1,l,r);
    query(k<<1|1,l,r);
}
void ask(int x,int y)
{
    int fx = top[x], fy = top[y];
    while(fx != fy){
        if(dep[fx] < dep[fy]) swap(x,y), swap(fx,fy);
        query(1,seg[fx],seg[x]);
        x = fa[fx]; fx = top[x];
    }
    if(dep[x] > dep[y]) swap(x,y);
    query(1,seg[x],seg[y]);
}
int main()
{
    int n = read();
    for(int i = 1,x,y; i < n; i++){
        x = read(); y = read();
        Add(x,y); Add(y,x);
    }
    for(int i = 1; i <= n; i++){
        num[i] = read();
    }
    dfs1(1,0);
    seg[0] = seg[1] = top[1] = rev[1] = 1;
    dfs2(1,0);
    build(1,1,seg[0]);
    int m = read();
    for(int i = 1,x,y; i <= m; i++){
        scanf("%s",s+1);
        x = read(); y = read();
        if(s[1] == 'C') update(1,seg[x],y);
        else{
            sum = 0; maxx = -3000000;
            ask(x,y);
            if(s[2] == 'M') printf("%d\n",maxx);
            else printf("%d\n",sum);
        }
    }
    return 0;
}