HDU 5274(樹鏈剖分）

樹鏈剖分第一題QAQ，紀念下

#pragma comment(linker, "/STACK:102400000,102400000")
#include 
#include 
#include 
using namespace std;
typedef long long ll;
const ll mod = 1e9 + 7;
const int maxn = 1e5 + 10;
#define to first
#define next second
#define foreach(it,v) for(__typeof(v.begin()) it = v.begin(); it != v.end(); ++it)
int pos[maxn],head[maxn],fa[maxn],son[maxn];
int a[maxn],siz[maxn],root[maxn],dep[maxn];
typedef pair Edge;
Edge edges[maxn<<1];
int e,tot;
void AddEdge(int u,int v)
{
    edges[++e] = make_pair(v,head[u]);head[u] = e;
    edges[++e] = make_pair(u,head[v]);head[v] = e;
}
void pre(int u)
{
    siz[u] = 1;son[u] = 0;
    dep[u] = dep[fa[u]] + 1;
    for(int i = head[u]; i ; i = edges[i].next) {
        int v = edges[i].to;
        if(v == fa[u])continue;
        fa[v] = u;
        pre(v);
        siz[u] += siz[v];
        if(siz[son[u]] < siz[v]) son[u] = v;
    }
}
void built(int u,int t)
{
    root[u] = t;
    pos[u] = ++tot;
    if(son[u] < 1) return;
    built(son[u],t);
    for(int i = head[u]; i ; i = edges[i].next) {
        int v = edges[i].to;
        if(v == fa[u] || v == son[u])continue;
        built(v,v);
    }
}
int seg[maxn<<2];
int ql,qr,x,v;
void Modify(int o,int L,int R)
{
    if(L == R) {
        seg[o] = v;
        return ;
    }
    int mid = (L+R)>>1;
    if(x<=mid) Modify(o<<1,L,mid);
    else Modify(o<<1|1,mid+1,R);
    seg[o] = seg[o<<1] ^ seg[o<<1|1];
}
int Queryseg(int o,int L,int R)
{
    if(ql<=L&&qr>=R) return seg[o];
    int mid = (L+R) >> 1;
    int res = 0;
    if(ql <= mid) res = Queryseg(o<<1,L,mid);
    if(qr > mid) res ^= Queryseg(o<<1|1,mid+1,R);
    return res;
}
int solve(int u,int v)
{
    int res = 0;
    while(root[u] != root[v]) {
        if(dep[root[u]] < dep[root[v]]) swap(u,v);
        ql = pos[root[u]],qr = pos[u];
        res ^= Queryseg(1,1,tot);
        u = fa[root[u]];
    }
    ql = pos[u],qr = pos[v];
    if(ql > qr) swap(ql,qr);
    res ^= Queryseg(1,1,tot);
    return res;
}
int main(int argc, char const *argv[])
{
    int T;scanf("%d",&T);
    while(T--) {
        int N,Q;scanf("%d%d",&N,&Q);
        dep[0] = e = tot = 0;
        memset(seg,0,sizeof seg);
        memset(head,0,sizeof(head[0])*(N+1));
        for(int i = 1; i < N; i++) {
            int u,v;scanf("%d%d",&u,&v);
            AddEdge(u,v);
        }
        fa[1] = siz[0] = 0;
        pre(1);
        built(1,1);
        for(int i = 1; i <= N; i++) {
            scanf("%d",&v); ++v; x = pos[i];
            Modify(1,1,tot);
        }
        while(Q--) {
            int op;scanf("%d",&op);
            if(op==0) {
                scanf("%d%d",&x,&v);x = pos[x]; ++v;
                Modify(1,1,tot);
            } else {
                scanf("%d%d",&ql,&qr);
                int ans = solve(ql,qr);
                printf("%d\n", ans - 1);
            }
        }
    }
    return 0;
}