bzoj1036 [ ZJOI2008 ] --树链剖分

模板题。。。

#include<iostream>#include<cstdio>#include<cstring>using namespace std;#define N 30001#define INF 1000000000inline char Nc(){    static char buf[100000],*p1=buf,*p2=buf;    if(p1==p2){        p2=(p1=buf)+fread(buf,1,100000,stdin);        if(p1==p2)return EOF;    }    return *p1++;}inline void Read(int& x){    char c=Nc(),b=1;    for(;c<'0'||c>'9';c=Nc())if(c=='-')b=-1;    for(x=0;c>='0'&&c<='9';x=x*10+c-48,c=Nc());x*=b;}inline void Read(char* s){    int i=0;    char c=Nc();    while(c!=' ')s[i]=c,i++,c=Nc();}int Len;char s[20];inline void Print(int x){    if(x<0){        putchar('-');        x=-x;    }    if(!x){        putchar('0');putchar('\n');        return;    }    for(Len=0;x;x/=10)s[++Len]=x%10;    for(;Len;Len--)putchar(s[Len]+48);    putchar('\n');}struct Edge{    int To,Next;}e[N<<1];inline int _Max(int x,int y){    return x>y?x:y;}int h[N],i,j,k,Num,n,m,T,a[N],w[N],x,y,w2[N],Top[N],Size[N],Son[N],f[N],Sum[N<<2],Max[N<<2],Deep[N];char S[20];inline void Add(int x,int y){    e[++Num].To=y;e[Num].Next=h[x];h[x]=Num;}void Dfs1(int x,int Fa){    f[x]=Fa;Size[x]=1;Deep[x]=Deep[Fa]+1;    for(int i=h[x];i;i=e[i].Next)    if(e[i].To!=Fa){        Dfs1(e[i].To,x);        Size[x]+=Size[e[i].To];        if(Size[e[i].To]>Size[Son[x]])Son[x]=e[i].To;    }}void Dfs2(int x,int Tmp){    w[x]=++m;w2[m]=x;Top[x]=Tmp;    if(Son[x])Dfs2(Son[x],Tmp);    for(int i=h[x];i;i=e[i].Next)    if(e[i].To!=f[x]&&e[i].To!=Son[x])Dfs2(e[i].To,e[i].To);}void Build(int Node,int l,int r){    if(l==r){        Sum[Node]=Max[Node]=a[w2[l]];        return;    }    int Mid=(l+r)>>1;    Build(Node<<1,l,Mid);    Build(Node<<1|1,Mid+1,r);    Sum[Node]=Sum[Node<<1]+Sum[Node<<1|1];    Max[Node]=_Max(Max[Node<<1],Max[Node<<1|1]);}void Update(int Node,int l,int r,int x,int y){    if(l==r){        Sum[Node]=Max[Node]=y;        return;    }    int Mid=(l+r)>>1;    if(x<=Mid)Update(Node<<1,l,Mid,x,y);else Update(Node<<1|1,Mid+1,r,x,y);    Sum[Node]=Sum[Node<<1]+Sum[Node<<1|1];    Max[Node]=_Max(Max[Node<<1],Max[Node<<1|1]);}int Querysum(int Node,int l,int r,int L,int R){    if(l>R||r<L)return 0;    if(l>=L&&r<=R)return Sum[Node];    int Mid=(l+r)>>1;    return Querysum(Node<<1,l,Mid,L,R)+Querysum(Node<<1|1,Mid+1,r,L,R);}int Querymax(int Node,int l,int r,int L,int R){    if(l>R||r<L)return -INF;    if(l>=L&&r<=R)return Max[Node];    int Mid=(l+r)>>1;    return _Max(Querymax(Node<<1,l,Mid,L,R),Querymax(Node<<1|1,Mid+1,r,L,R));}int Querysum_tree(int u,int v){    int Ans=0;    while(Top[u]!=Top[v])    if(Deep[Top[u]]<Deep[Top[v]]){        Ans+=Querysum(1,1,m,w[Top[v]],w[v]);        v=f[Top[v]];    }else{        Ans+=Querysum(1,1,m,w[Top[u]],w[u]);        u=f[Top[u]];    }    if(w[u]<w[v])Ans+=Querysum(1,1,m,w[u],w[v]);else Ans+=Querysum(1,1,m,w[v],w[u]);    return Ans;}int Querymax_tree(int u,int v){    int Ans=-INF;    while(Top[u]!=Top[v])    if(Deep[Top[u]]<Deep[Top[v]]){        Ans=_Max(Ans,Querymax(1,1,m,w[Top[v]],w[v]));        v=f[Top[v]];    }else{        Ans=_Max(Ans,Querymax(1,1,m,w[Top[u]],w[u]));        u=f[Top[u]];    }    if(w[u]<w[v])Ans=_Max(Ans,Querymax(1,1,m,w[u],w[v]));else Ans=_Max(Ans,Querymax(1,1,m,w[v],w[u]));    return Ans;}int main(){    Read(n);    for(i=1;i<n;i++){        Read(x);Read(y);        Add(x,y);        Add(y,x);    }    for(i=1;i<=n;i++)Read(a[i]);    Dfs1(1,0);    Dfs2(1,1);    Build(1,1,m);    Read(T);    while(T--){        Read(S);Read(x);Read(y);        if(S[0]=='C')Update(1,1,m,w[x],y);else        if(S[1]=='S')Print(Querysum_tree(x,y));else Print(Querymax_tree(x,y));    }    return 0;}