poj3237Tree 【树链剖分+线段树】

来源：互联网发布：单片机初始化程序8255 编辑：程序博客网时间：2024/06/13 19:55
#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <stack>#include <set>#include <map>#include <string>#include <cmath>#include <stdlib.h>#include <time.h>using namespace std;const int inf=0x7fffffff;const int N=10000+10;struct edge{    int a,b,w;}g[2*N];vector<int>v[N];int fa[N],dep[N],sz[N],son[N],w[N],tot,top[N];struct Tree{    int l,r,f,mx,mi;}tree[4*N];void build(int o,int l,int r){    tree[o].l=l;    tree[o].r=r;    tree[o].f=0;    tree[o].mx=0;    tree[o].mi=0;    if(l!=r)    {        int mid=(l+r)/2;        build(o*2,l,mid);        build(o*2+1,mid+1,r);    }}void pushdown(int o){    if(tree[o].l==tree[o].r) return ;    if(tree[o].f)    {        tree[o*2].f^=1;        tree[o*2+1].f^=1;        swap(tree[o*2].mx,tree[o*2].mi);        tree[o*2].mx=-tree[o*2].mx;        tree[o*2].mi=-tree[o*2].mi;        swap(tree[o*2+1].mx,tree[o*2+1].mi);        tree[o*2+1].mx=-tree[o*2+1].mx;        tree[o*2+1].mi=-tree[o*2+1].mi;        tree[o].f=0;    }}void update(int o,int l,int r,int val){    if(l==tree[o].l&&tree[o].r==r)    {        tree[o].mx=tree[o].mi=val;        tree[o].f=0;    }    else    {        pushdown(o);        int mid=(tree[o].l+tree[o].r)/2;        if(l<=mid)  update(o*2,l,r,val);        else update(o*2+1,l,r,val);        tree[o].mx=max(tree[o*2].mx,tree[o*2+1].mx);        tree[o].mi=min(tree[o*2].mi,tree[o*2+1].mi);    }}void update2(int o,int l,int r){    if(l==tree[o].l&&tree[o].r==r)    {        swap(tree[o].mx,tree[o].mi);        tree[o].mx=-tree[o].mx;        tree[o].mi=-tree[o].mi;        tree[o].f^=1;    }    else    {        pushdown(o);        int mid=(tree[o].l+tree[o].r)/2;        if(r<=mid)  update2(o*2,l,r);        else if(l>mid) update2(o*2+1,l,r);        else        {            update2(o*2,l,mid);            update2(o*2+1,mid+1,r);        }        tree[o].mx=max(tree[o*2].mx,tree[o*2+1].mx);        tree[o].mi=min(tree[o*2].mi,tree[o*2+1].mi);    }}int query(int o,int l,int r){    if(l==tree[o].l&&tree[o].r==r)    {       return tree[o].mx;    }    else    {        pushdown(o);        int mid=(tree[o].l+tree[o].r)/2;        if(r<=mid) return query(o*2,l,r);        else if(l>mid) return query(o*2+1,l,r);        else return max(query(o*2,l,mid),query(o*2+1,mid+1,r));         tree[o].mx=max(tree[o*2].mx,tree[o*2+1].mx);        tree[o].mi=min(tree[o*2].mi,tree[o*2+1].mi);    }}void dfs1(int x,int f){    fa[x]=f;    dep[x]=dep[f]+1;    sz[x]=1;    int m=0,y;    for(int i=0;i<v[x].size();i++)    {        y=v[x][i];        if(y==f) continue;        dfs1(y,x);        sz[x]+=sz[y];        if(m==0||sz[y]>sz[m])        {            son[x]=y;            m=y;        }    }}void dfs2(int x,int tp){    top[x]=tp;    if(son[x]!=0)    {        w[x]=++tot;        dfs2(son[x],tp);    }    else    {        w[x]=++tot;        return ;    }    int y;    for(int i=0;i<v[x].size();i++)    {        y=v[x][i];        if(y!=son[x]&&y!=fa[x])            dfs2(y,y);    }}int Find(int x,int y){    int f1=top[x],f2=top[y];    int tmp=-inf;    while(f1!=f2)    {        if(dep[f1]<dep[f2])        {            swap(f1,f2);            swap(x,y);        }        tmp=max(tmp,query(1,w[f1],w[x]));        x=fa[f1];        f1=top[x];    }    if(x==y) return tmp;    if(dep[x]>dep[y]) swap(x,y);    return max(tmp,query(1,w[son[x]],w[y]));}void change(int x,int y){    int f1=top[x],f2=top[y];    while(f1!=f2)    {        if(dep[f1]<dep[f2])        {            swap(f1,f2);            swap(x,y);        }        update2(1,w[f1],w[x]);        x=fa[f1];        f1=top[x];    }    if(x==y) return ;    if(dep[x]>dep[y]) swap(x,y);    update2(1,w[son[x]],w[y]);}int main(){    int _,a,b,n,c;    char s[1024];    //freopen("out.txt","w",stdout);    scanf("%d",&_);    while(_--)    {        scanf("%d",&n);        tot=0;        for(int i=0;i<=n;i++)            v[i].clear();        for(int i=0;i<n-1;i++)        {            scanf("%d%d%d",&a,&b,&c);            g[i].a=a;            g[i].b=b;            g[i].w=c;            v[a].push_back(b);            v[b].push_back(a);        }        dep[0]=0;        memset(son,0,sizeof(son));        dfs1(1,0);        dfs2(1,1);        build(1,1,tot);        for(int i=0;i<n-1;i++)        {            if(dep[g[i].a]>dep[g[i].b])                swap(g[i].a,g[i].b);            update(1,w[g[i].b],w[g[i].b],g[i].w);        }        while(~scanf("%s",s))        {            if(s[0]=='Q')            {                scanf("%d%d",&a,&b);                printf("%d\n",Find(a,b));            }            else if(s[0]=='C')            {                scanf("%d%d",&a,&b);                update(1,w[g[a-1].b],w[g[a-1].b],b);            }            else if(s[0]=='N')            {                scanf("%d%d",&a,&b);                change(a,b);            }            else                break;        }    }    return 0;}
0 0