树的统计（树剖）指针版

来源：互联网发布：acrobat xi mac 破解编辑：程序博客网时间：2024/06/16 20:04
题目>>http://codevs.cn/problem/2460/
#include<iostream>#include<cstdio>#include<algorithm>#include<cstring>using namespace std;const int MAXN = 1e6 + 5;typedef long long ll;ll n,a,b,num[MAXN],q,firs[MAXN],nex[MAXN],cnt = 0;char s[15];struct zt{    ll f,t;}road[MAXN];void build(ll f,ll t){    road[++cnt] = (zt){f,t};    nex[cnt] = firs[f];    firs[f] = cnt;} ll fa[MAXN],son[MAXN],sz[MAXN],deep[MAXN];void dfs1(ll x,ll f){    fa[x] = f;    deep[x] = deep[f] + 1;    sz[x] = 1;    for(int i = firs[x];i != -1;i = nex[i])    {        ll v = road[i].t;        if(v != f)        {            dfs1(v,x);            sz[x] += sz[v];            if(!son[x]||sz[v] > sz[son[x]]) son[x] = v;        }    }}ll intu[MAXN],top[MAXN],tot = 0;void dfs2(ll x,ll topx){    top[x] = topx;    intu[x] = ++tot;    if(!son[x]) return;    dfs2(son[x],topx);    for(int i = firs[x];i != -1;i = nex[i])    {        int v = road[i].t;        if(v != fa[x]&&v != son[x])            dfs2(v,v);    } }struct dd{    ll sum,maxn;    dd *lift,*right;}tree[MAXN];ll cc = 0;void hs(dd *root){    root->sum = root->lift->sum + root->right->sum;    root->maxn = max(root->lift->maxn,root->right->maxn);}void build_tree(dd *root,ll l,ll r){    root->sum = 0;root->maxn = 0;    if(l == r)        return;    ll mid = l + r >>1;    root->right = &tree[++cc];    root->lift = &tree[++cc];    build_tree(root->lift,l,mid);    build_tree(root->right,mid + 1,r);    hs(root);}void change(dd *root,ll l,ll r,ll q,ll x){    if(l == r)    {        root->sum = root->maxn = x;        return;    }    ll mid = l + r >> 1;    if(q <= mid)    change(root->lift,l,mid,q,x);    else    change(root->right,mid + 1,r,q,x);    hs(root);}ll ask_sum(dd *root,ll l,ll r,ll ql,ll qr){    if(l >= ql&&qr >= r)        return root->sum;    ll mid = l + r >> 1,ans = 0;    if(ql <= mid)   ans += ask_sum(root->lift,l,mid,ql,qr);    if(qr > mid)    ans += ask_sum(root->right,mid + 1,r,ql,qr);    return ans;}ll find_sum(ll x,ll y){    ll xt = top[x],yt = top[y],ans = 0;    while(xt != yt)    {        if(deep[xt] < deep[yt]) swap(xt,yt),swap(x,y);        ans += ask_sum(tree,1,n,intu[xt],intu[x]);        x = fa[xt];xt = top[x];    }    if(deep[x] > deep[y])   swap(x,y);    ans += ask_sum(tree,1,n,intu[x],intu[y]);    return ans;}ll ask_max(dd *root,ll l,ll r,ll ql,ll qr){    if(l >= ql&&qr >= r)        return root->maxn;    ll mid = l + r >> 1,ans = -1e6;    if(ql <= mid)   ans = max(ask_max(root->lift,l,mid,ql,qr),ans);    if(qr > mid)    ans = max(ask_max(root->right,mid + 1,r,ql,qr),ans);    return ans;}ll find_max(ll x,ll y){    ll xt = top[x],yt = top[y],ans = -1e6;    while(xt != yt)    {        if(deep[xt] < deep[yt]) swap(xt,yt),swap(x,y);        ans = max(ask_max(tree,1,n,intu[xt],intu[x]),ans);        x = fa[xt];xt = top[x];    }    if(deep[x] > deep[y])   swap(x,y);    ans = max(ask_max(tree,1,n,intu[x],intu[y]),ans);    return ans;}int main(){    scanf("%lld",&n);    for(int i = 1;i <= n;i ++)        firs[i] = -1;    for(int i = 1;i < n;i ++)    {        scanf("%lld%lld",&a,&b);        build(a,b);        build(b,a);     }    dfs1(1,0);    dfs2(1,1);    build_tree(tree,1,n);     for(int i = 1;i <= n; i++)    {        scanf("%lld",&a);        change(tree,1,n,intu[i],a);    }       scanf("%lld",&q);    for(int i = 1;i <= q;i ++)    {        scanf("%s%lld%lld",s,&a,&b);        if(s[0] == 'C') change(tree,1,n,intu[a],b),num[a] = b;        else if(s[1] == 'M')    cout<<find_max(a,b)<<'\n';        else cout<<find_sum(a,b)<<'\n';    }}
阅读全文
0 0