ZJOI2008 树的统计 树链剖分学习

水题，这次都没有给我傻逼的机会了，1A过了。直接上代码了

#include <iostream>#include <cstdio>#include <cstring>#include <cmath>#include <algorithm>#define LL long long#define INF 0x3fffffff#define FOR(i,x,y)  for(int i = x;i < y;i ++)#define IFOR(i,x,y) for(int i = x;i > y;i --)#define lrt rt<<1#define rrt rt<<1|1#define lson rt<<1,l,mid#define rson rt<<1|1,mid+1,r#define MAXN 33000using namespace std;int n,p;struct Edge{    int u,v;    int nt;}edge[MAXN<<1];int head[MAXN],edge_cnt;void add_edge(int u,int v){    edge[edge_cnt].u = u;    edge[edge_cnt].v = v;    edge[edge_cnt].nt = head[u];    head[u] = edge_cnt++;}int val0[MAXN];int fa[MAXN],sz[MAXN],son[MAXN],dep[MAXN],top[MAXN],w[MAXN],val[MAXN];int totw;void dfs1(int u,int father,int depth){    fa[u] = father; dep[u] = depth; sz[u] = 1;    int idd = -1,maxx = -1;    for(int i = head[u];i != -1;i = edge[i].nt){        int v = edge[i].v;        if(v == father) continue;        dfs1(v,u,depth+1);        sz[u] += sz[v];        if(maxx < sz[v])    {maxx = sz[v];idd = v;}    }    son[u] = idd;}void dfs2(int u,int father){    if(son[u] == -1)    return;    top[son[u]] = top[u];    w[son[u]] = ++totw;    val[totw] = val0[son[u]];    dfs2(son[u],u);    for(int i = head[u];i != -1;i = edge[i].nt){        int v = edge[i].v;        if(v == father) continue;        if(v == son[u]) continue;        top[v] = v;        w[v] = ++totw;        val[totw] = val0[v];        dfs2(v,u);    }}struct Tree{    int l,r;    int maxx,sum;}tree[MAXN<<2];void PushUp(int rt){    tree[rt].maxx = max(tree[lrt].maxx,tree[rrt].maxx);    tree[rt].sum = tree[lrt].sum + tree[rrt].sum;}void Build(int rt,int l,int r){    tree[rt].l = l; tree[rt].r = r;    if(l == r){        tree[rt].maxx = tree[rt].sum = val[l];        return;    }    int mid = (l+r)>>1;    Build(lson);    Build(rson);    PushUp(rt);}void Modify(int rt,int x,int value){    if(tree[rt].l == tree[rt].r){        tree[rt].maxx = tree[rt].sum = value;        return;    }    int mid = (tree[rt].l + tree[rt].r)>>1;    if(x <= mid) Modify(lrt,x,value);    else Modify(rrt,x,value);    PushUp(rt);}int Q_Max(int rt,int l,int r){    if(tree[rt].l == l && tree[rt].r == r){        return tree[rt].maxx;    }    int mid = (tree[rt].l + tree[rt].r)>>1;    if(r <= mid) return Q_Max(lrt,l,r);    else if(l > mid) return Q_Max(rrt,l,r);    else{        return max(Q_Max(lson),Q_Max(rson));    }}int Q_Sum(int rt,int l,int r){    if(tree[rt].l == l && tree[rt].r == r){        return tree[rt].sum;    }    int mid = (tree[rt].l + tree[rt].r)>>1;    if(r <= mid) return Q_Sum(lrt,l,r);    else if(l > mid) return Q_Sum(rrt,l,r);    else{        return Q_Sum(lson)+Q_Sum(rson);    }}int Max(int l,int r){    int ans = -INF;    while(top[l] != top[r]){        if(dep[top[l]] >= dep[top[r]]){            ans = max(ans,Q_Max(1,w[top[l]],w[l]));            l = fa[top[l]];        }        else{            ans = max(ans,Q_Max(1,w[top[r]],w[r]));            r = fa[top[r]];        }    }    if(l == r)  ans = max(ans,Q_Max(1,w[l],w[r]));    else if(dep[l] >= dep[r]){        ans = max(ans,Q_Max(1,w[r],w[l]));    }    else ans = max(ans,Q_Max(1,w[l],w[r]));    return ans;}int Sum(int l,int r){    int ans = 0;    while(top[l] != top[r]){        if(dep[top[l]] >= dep[top[r]]){            ans += Q_Sum(1,w[top[l]],w[l]);            l = fa[top[l]];        }        else{            ans += Q_Sum(1,w[top[r]],w[r]);            r = fa[top[r]];        }    }    if(l == r)  ans += Q_Sum(1,w[l],w[r]);    else if(dep[l] >= dep[r]) ans += Q_Sum(1,w[r],w[l]);    else ans += Q_Sum(1,w[l],w[r]);    return ans;}int main(){    //freopen("test.in","r",stdin);    while(~scanf("%d",&n)){        edge_cnt = 0;        memset(head,-1,sizeof(head));        FOR(i,1,n){            int u,v;            scanf("%d%d",&u,&v);            add_edge(u,v);            add_edge(v,u);        }        FOR(i,1,n+1)    scanf("%d",&val0[i]);        dfs1(1,-1,1);        totw = 0;        top[1] = 1;        val[1] = val0[1];        w[1] = ++totw;        dfs2(1,-1);        Build(1,1,totw);        scanf("%d",&p);        char op[10];        while(p--){            scanf("%s",op);            if(!strcmp(op,"CHANGE")){                int u,t;                scanf("%d%d",&u,&t);                Modify(1,w[u],t);            }            else if(!strcmp(op,"QMAX")){                int l,r;                scanf("%d%d",&l,&r);                printf("%d\n",Max(l,r));            }            else{                int l,r;                scanf("%d%d",&l,&r);                printf("%d\n",Sum(l,r));            }        }    }    return 0;}