bzoj 2001 [Hnoi2010]City 城市建设 cdq分治

#include<iostream>
#include<algorithm>
#include<cstdio>
#include<cstring>
using namespace std;
typedef long long ll;
#define N 50010
#define inf 0x6fffffffffLL
struct P{
    int x,y;
    ll w,org;
    int num;
    bool operator<(P a)const{
       return w<a.w;
    }
}c[N*40];
int cn;
int bb[N*40],bn;
int f1[N],f2[N];
int get1(int x){
    return f1[x]==x?x:f1[x]=get1(f1[x]);
}
int get2(int x){
    return f2[x]==x?x:f2[x]=get2(f2[x]);
}
bool he(int x,int y){
    int x1=get1(x),y1=get1(y);
    if(x1==y1)return 0;
    else return f1[x1]=y1,1;
}
void he2(int x,int y){
    int x1=get2(x),y1=get2(y);
    if(x1!=y1)f2[x1]=y1;
}
P w1[N],w2[N];
int wn1,wn2;
ll ans[N];
int ch[N];
ll to[N];
int h[N];
int n,m,q;
void solv(int L,int R,int cl,int cr,int bl,int br,ll res){
    int rb=bn,rc=cn,p,j;
    wn1=0,wn2=0;
    for(int i=bl;i<=br;i++)f1[bb[i]]=bb[i],f2[bb[i]]=bb[i];
    for(int i=cl;i<=cr;i++)w1[++wn1]=c[i],h[c[i].num]=wn1;
    if(L==R){
        p=h[ch[L]];
        w1[p].w=to[L];
        sort(w1+1,w1+wn1+1);
        for(int i=1;i<=wn1;i++)if(he(w1[i].x,w1[i].y))res+=w1[i].w;
        ans[L]=res;
        return;
    }
    for(int i=L;i<=R;i++){
        p=h[ch[i]];
        if(w1[p].w==-inf)continue;
        w1[p].org=w1[p].w;
        w1[p].w=-inf;
    }
    sort(w1+1,w1+wn1+1);
    for(int i=1;i<=wn1;i++){
        p=w1[i].x,j=w1[i].y;
        if(he(p,j)){
            if(w1[i].w!=-inf)he2(p,j),res+=w1[i].w;
        }
    }
    for(int i=bl;i<=br;i++)if(f2[bb[i]]==bb[i])bb[++bn]=bb[i];
    for(int i=1;i<=wn1;i++){
        p=get2(w1[i].x),j=get2(w1[i].y);
        if(p!=j){
            w2[++wn2]=w1[i];
            w2[wn2].x=p,w2[wn2].y=j;
        }
    }
    for(int i=1;i<=wn2;i++)if(w2[i].w==-inf)w2[i].w=inf;
    sort(w2+1,w2+wn2+1);
    for(int i=bl;i<=br;i++)f1[bb[i]]=bb[i];
    for(int i=1;i<=wn2;i++){
        if(he(w2[i].x,w2[i].y)){
            if(w2[i].w!=inf)c[++cn]=w2[i];
        }
    }
    for(int i=1;i<=wn2;i++)if(w2[i].w==inf){
        c[++cn]=w2[i];
        c[cn].w=w2[i].org;
    }
    int mid=(L+R)>>1;
    int r1=cn,r2=bn;
    solv(L,mid,rc+1,r1,rb+1,r2,res);
    for(int i=rc+1;i<=r1;i++)h[c[i].num]=i;
    for(int i=L;i<=mid;i++)c[h[ch[i]]].w=to[i];
    solv(mid+1,R,rc+1,r1,rb+1,r2,res);
}
int main(){
    scanf("%d%d%d",&n,&m,&q);
    for(int i=1;i<=m;i++){
        scanf("%d%d%lld",&c[i].x,&c[i].y,&c[i].w);
        c[i].num=i;
    }
    for(int i=1;i<=q;i++){
        scanf("%d%lld",&ch[i],&to[i]);
    }
    for(int i=1;i<=n;i++)bb[i]=i;
    cn=m;
    bn=n;
    solv(1,q,1,m,1,n,0);
    for(int i=1;i<=q;i++){
        printf("%lld\n",ans[i]);
    }
    
}