hdu 3966 Aragorn's Story（树链剖分）

kuangbin大佬模板里的，点权的模板。。。

#include <bits/stdc++.h>using namespace std;const int MAXN = 50010;struct Edge{    int to,next;} edge[MAXN*2];int head[MAXN],tot;int top[MAXN];int fa[MAXN];int dep[MAXN];int num[MAXN];int p[MAXN];int son[MAXN];int pos,n,c[MAXN];int a[MAXN];void init(){    tot = 0;    memset(head,-1,sizeof(head));    pos = 1;//使用树状数组，编号从头1开始    memset(son,-1,sizeof(son));}void addedge(int u,int v){    edge[tot].to = v;    edge[tot].next = head[u];    head[u] = tot++;}void dfs1(int u, int pre, int d){    dep[u] = d;    fa[u] = pre;    num[u] = 1;    for(int i = head[u]; i != -1; i = edge[i].next)    {        int v = edge[i].to;        if(v == pre) continue;        dfs1(v,u,d+1);        num[u] += num[v];        if(son[u] == -1 || num[v] > num[son[u]])            son[u] = v;    }}void getpos(int u, int sp){    top[u] = sp;    p[u] = pos++;    if(son[u] == -1) return;    getpos(son[u],sp);    for(int i = head[u]; i != -1; i = edge[i].next)    {        int v = edge[i].to;        if(v != son[u] && v != fa[u])            getpos(v,v);    }}int lowbit(int x){    return x&(-x);}int sum(int i){    int s = 0;    while(i > 0)    {        s += c[i];        i -= lowbit(i);    }    return s;}void add(int i, int val){    while(i <= n)    {        c[i] += val;        i += lowbit(i);    }}void Change(int u, int v, int val){    int f1 = top[u];    int f2 = top[v];    while(f1 != f2)    {        if(dep[f1] < dep[f2])        {            swap(f1,f2);            swap(u,v);        }        add(p[f1],val);        add(p[u]+1,-val);        u = fa[f1];        f1 = top[u];    }    if(dep[u] > dep[v]) swap(u,v);    add(p[u],val);    add(p[v]+1,-val);}int main(){    int M,P;    while(scanf("%d %d %d",&n,&M,&P) != EOF)    {        int u,v;        int C1,C2,K;        char op[10];        init();        for(int i = 1; i <= n; ++i)            scanf("%d",&a[i]);        while(M--)        {            scanf("%d %d",&u,&v);            addedge(u,v);            addedge(v,u);        }        dfs1(1,0,0);        getpos(1,1);        memset(c,0,sizeof(c));        for(int i = 1; i <= n; ++i)        {            add(p[i],a[i]);            add(p[i]+1,-a[i]);        }        while(P--)        {            scanf(" %s",op);            if(op[0] == 'Q')            {                scanf("%d",&u);                printf("%d\n",sum(p[u]));            }            else            {                scanf("%d %d %d",&C1,&C2,&K);                if(op[0] == 'D')                    K = -K;                Change(C1,C2,K);            }        }    }    return 0;}