bzoj 4034（树链剖分）

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考前复习模板题（子树修改，单点修改，链上求和）。

一晚上狂TLE，原因竟是：链剖siz比较写错，写了个轻链剖分。。。

#include<bits/stdc++.h>using namespace std;#define lson rt<<1,l,mid#define rson rt<<1|1,mid+1,r#define root 1,1,ntypedef long long ll;const int MAXN=1e5+4;int n,m,a[MAXN];vector<int > g[MAXN];int fa[MAXN],dep[MAXN],siz[MAXN],son[MAXN],top[MAXN],in[MAXN],out[MAXN],rk[MAXN],tim=0;/*------------DCP------------*/void dfs1(int p,int father,int d) {siz[p]=1,dep[p]=d,fa[p]=father;for (int i=0;i<g[p].size();++i) {int v=g[p][i];if (v^father) {dfs1(v,p,d+1);siz[p]+=siz[v];if (son[p]==-1||siz[v]>siz[son[p]])son[p]=v;}}}void dfs2(int p,int tp) {top[p]=tp,in[p]=++tim,rk[tim]=p;if (~son[p]) dfs2(son[p],tp);for (int i=0;i<g[p].size();++i) {int v=g[p][i];if (v^fa[p]&&v^son[p])dfs2(v,v);}out[p]=tim;}/*------------Segment Tree------------*/ll sum[MAXN<<2],laz[MAXN<<2];void build(int rt,int l,int r) {laz[rt]=0;if (l==r) {sum[rt]=a[rk[l]];return ;}int mid=l+r>>1;build(lson);build(rson);sum[rt]=sum[rt<<1]+sum[rt<<1|1];}inline void pushdown(int rt,int len) {if (laz[rt]) {laz[rt<<1]+=laz[rt];laz[rt<<1|1]+=laz[rt];sum[rt<<1]+=laz[rt]*(len-(len>>1));sum[rt<<1|1]+=laz[rt]*(len>>1);laz[rt]=0;}}void modify(int rt,int l,int r,int L,int R,ll val) {if (L<=l&&r<=R) {sum[rt]+=val*(r-l+1);laz[rt]+=val;return ;}pushdown(rt,r-l+1);int mid=l+r>>1;if (L<=mid) modify(lson,L,R,val);if (mid<R) modify(rson,L,R,val);sum[rt]=sum[rt<<1]+sum[rt<<1|1];}ll query(int rt,int l,int r,int L,int R) {if (L<=l&&r<=R) return sum[rt];pushdown(rt,r-l+1);int mid=l+r>>1;ll ret=0;if (L<=mid) ret+=query(lson,L,R);if (mid<R) ret+=query(rson,L,R);return ret;}ll ask(int x,int y) {ll ret=0;while (top[x]^top[y]) {if (dep[top[x]]<dep[top[y]]) x^=y^=x^=y;ret+=query(root,in[top[x]],in[x]);x=fa[top[x]];}if (dep[x]<dep[y]) x^=y^=x^=y;ret+=query(root,in[y],in[x]);return ret;}inline int read() {int x=0,f=1;char c=getchar();while (c<'0'||c>'9') {if (c=='-') f=-1;c=getchar();}while (c>='0'&&c<='9') x=x*10+c-'0',c=getchar();return x*f;}int main() {//freopen("bzoj 4034.in","r",stdin);memset(son,-1,sizeof(son));n=read(),m=read();for (register int i=1;i<=n;++i) a[i]=read(),g[i].clear();for (register int i=1;i<n;++i) {int u=read(),v=read();g[u].push_back(v);g[v].push_back(u);}dfs1(1,0,1);dfs2(1,1);build(root);for (register int i=0;i<m;++i) {int opt=read();switch (opt) {case 1:{int x=read();ll v=read();modify(root,in[x],in[x],v);break;}case 2:{int x=read();ll v=read();modify(root,in[x],out[x],v);break;}case 3:{int x=read();printf("%lld\n",ask(1,x));break;}}}return 0;}

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