标签：剖分 int ll 树链 Fa ZJOI2015 root top dis

最近写动态点分治快自闭了QAQ.......

有时间再来写一下题解. 

其实我不会告诉你我还没调出来呢QAQ

Code:

// luogu-judger-enable-o2
// luogu-judger-enable-o2
#include <bits/stdc++.h>
#define setIO(s) freopen(s".in","r",stdin) // ,freopen(s".out","w",stdout) 
#define maxn 300000 
#define N 300010     
#define ll long long  
#define inf 0x7f7f7f 
using namespace std;
int n,m,cnt,sn,root; 
int hd[N],to[N],nx[N],val[N]; 
void add(int u,int v,int c)
{
    nx[++cnt] = hd[u],hd[u] = cnt,to[cnt] = v,val[cnt] = c; 
}
namespace heavyedge
{
    int fa[N],hson[N],siz[N],top[N],dep[N];
    ll dis[N];      
    void dfs1(int u,int ff)
    {
        fa[u] = ff;  
        for(int i = hd[u]; i ; i = nx[i])
        {
            if(to[i] == ff) continue; 
            dep[to[i]] = dep[u] + 1,dis[to[i]] = dis[u] + val[i]; 
            dfs1(to[i],u); 
            siz[u] += siz[to[i]]; 
            if(siz[to[i]] > siz[hson[u]]) hson[u] = to[i]; 
        }
    }
    void dfs2(int u,int tp)
    {
        top[u] = tp;
        if(hson[u]) dfs2(hson[u],tp); 
        for(int i = hd[u]; i ; i = nx[i])
        {
            if(to[i] == hson[u] || to[i] == fa[u]) continue; 
            dfs2(to[i],to[i]); 
        }
    }
    int LCA(int a,int b)
    { 
        while(top[a] != top[b]) dep[top[a]] < dep[top[b]] ? b = fa[top[b]]: a = fa[top[a]]; 
        return dep[a] < dep[b] ? a : b; 
    }
    int main()
    {
        dfs1(1,0),dfs2(1,1); 
        return 0; 
    }
}; 
ll Dis(int a,int b)
{
    return heavyedge::dis[a] + heavyedge::dis[b] - (heavyedge::dis[heavyedge::LCA(a,b)] << 1); 
}
int siz[N],vis[N],Fa[N],hto[N],f[N],tmp;  
ll sumv[N],sumd[N]; 
void GetRoot(int u,int ff)
{ 
    siz[u] = 1,f[u] = 0; 
    for(int i = hd[u]; i ; i = nx[i])
    {
        if(vis[to[i]] || to[i] == ff) continue;          
        GetRoot(to[i],u); 
        siz[u] += siz[to[i]]; 
        f[u] = max(f[u],siz[to[i]]); 
    }
    f[u] = max(f[u],sn - siz[u]); 
    if(f[root] > f[u]) root = u; 
}
void dfs(int u)
{
    vis[u] = 1; 
    for(int i = hd[u]; i ; i = nx[i])
    {
        if(vis[to[i]]) continue; 
        root = 0, sn = siz[to[i]], GetRoot(to[i],u), hto[i] = root,Fa[root] = u, dfs(root); 
    }
} 
#define fax(i) (i + n)
void Update(int x,int w)
{
    sumv[x] += w; 
    for(int i = x; Fa[i]; i = Fa[i])
    {  
        ll dis = Dis(x, Fa[i]);         
        sumv[Fa[i]] += w;
        sumd[Fa[i]] += 1ll*dis * w;
        sumd[fax(i)] += 1ll*dis * w; 
    }                            
}
ll calc(int x)
{
    ll res = sumd[x];  
    for(int i = x; Fa[i]; i = Fa[i])
    {
        ll dis = Dis(x, Fa[i]); 
        res += 1ll*(sumv[Fa[i]] - sumv[i]) * dis; 
        res += sumd[Fa[i]] - sumd[fax(i)]; 
    }
    return res;    
}
ll Query(int u)
{
    ll tmp = calc(u); 
    for(int i = hd[u]; i ; i = nx[i])
    {
        if(calc(to[i]) < tmp) return Query(to[i]); 
    }
    return tmp; 
}
int main()
{

    scanf("%d%d",&n,&m);          
    for(int i = 1,a,b,c;i < n; ++i) scanf("%d%d%d",&a,&b,&c),add(a,b,c),add(b,a,c);
    heavyedge :: main();     
    f[0] = inf, sn = n, root = 0, GetRoot(1,0),tmp = root,dfs(root), root = tmp;
    int u,e;  
    while(m--)
    {
        scanf("%d%d",&u,&e),Update(u,e),printf("%lld\n",Query(root)); 
    }
    return 0;  
}

标签：剖分,int,ll,树链,Fa,ZJOI2015,root,top,dis
来源： https://www.cnblogs.com/guangheli/p/10922843.html

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