码风优良，$WA\ on \#2\ 141,\#3\ 191,\#9\ 1382$

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
ll read() {
	ll x=0,f=1;
	char ch=getchar();
	while(ch<'0'||ch>'9') {
		if(ch=='-') f=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9') {
		x=x*10+ch-'0';
		ch=getchar();
	}
	return x*f;
}
const ll N=1e5+10;
ll n,_;
vector<pair<ll,ll> > e[N];
struct Edge{
	ll u,v,w;
}edge[N];
ll op,x,y,cnt,ring_pos;
ll top[N],sz[N],fa[N],deep[N],dfn[N],ww[N],last_w[N],son[N];
struct Segmentree{
	ll l,r,sum;
}t[N*4];
void build(ll q,ll l,ll r){
	t[q].l=l;
	t[q].r=r;
	if(l==r){
		t[q].sum=last_w[l];
		return ;
	}
	ll mid=(l+r)/2;
	build(q*2,l,mid);
	build(q*2+1,mid+1,r);
	t[q].sum=t[q*2].sum+t[q*2+1].sum;
}
void change(ll q,ll seat,ll d){
	if(t[q].l==t[q].r){
		t[q].sum=d;
		return ;
	}
	ll mid=(t[q].l+t[q].r)/2;
	if(seat<=mid) change(q*2,seat,d);
	else change(q*2+1,seat,d);
	t[q].sum=t[q*2].sum+t[q*2+1].sum;
}
ll ask(ll q,ll l,ll r){
	if(t[q].l>=l&&t[q].r<=r) return t[q].sum;
	ll sum=0,mid=(t[q].l+t[q].r)/2;
	if(l<=mid) sum+=ask(q*2,l,r);
	if(r>mid) sum+=ask(q*2+1,l,r);
	return sum;
}
ll Ask_LCA(ll u,ll v){
	ll sum=0;
	while(top[u]!=top[v]){
		if(deep[top[u]]<deep[top[v]]) swap(u,v);
		sum+=ask(1,dfn[top[u]],dfn[u]);
		u=fa[top[u]];
	}
	if(u==v) return sum;
	if(deep[u]>deep[v]) swap(u,v);
	sum+=ask(1,dfn[u]+1,dfn[v]);
	return sum;
}
ll find(ll t){
	return fa[t]==t?t:fa[t]=find(fa[t]);
}
void dfs1(ll t,ll last){
	sz[t]=1;
	fa[t]=last;
	deep[t]=deep[last]+1;
	for (int i=0;i<e[t].size();i++){
		if(e[t][i].first==last) continue;
		dfs1(e[t][i].first,t);
		sz[t]+=sz[e[t][i].first];
		ww[e[t][i].first]=e[t][i].second;
		if(sz[son[t]]<sz[e[t][i].first]) son[t]=e[t][i].first;
	}
}
void dfs2(ll tp,ll t){
	top[t]=tp;
	dfn[t]=cnt;
	last_w[cnt]=ww[t];
	cnt++;
	if(son[t]==0) return ;
	dfs2(tp,son[t]);
	for (int i=0;i<e[t].size();i++){
		if(e[t][i].first==fa[t]||e[t][i].first==son[t]) continue;
		dfs2(e[t][i].first,e[t][i].first);
	}
}
signed main(){
	n=read();
	_=read();
	for (int i=1;i<=n;i++) fa[i]=i;
	for (int i=1;i<=n;i++){
		edge[i].u=read();
		edge[i].v=read();
		edge[i].w=read();
		ll uu=find(edge[i].u);
		ll vv=find(edge[i].v);
		if(uu==vv) ring_pos=i;
		else {
			fa[uu]=vv;
			e[edge[i].u].push_back(make_pair(edge[i].v,edge[i].w));
			e[edge[i].v].push_back(make_pair(edge[i].u,edge[i].w));
		}
	}
	cnt=0;
	dfs1(1,0);
	dfs2(1,1);
	cnt--;
	build(1,1,cnt);
	while(_--){
		op=read();
		x=read();
		y=read();
		if(op==1){
			edge[x].w=y;
			ll tmp;
			if(deep[edge[x].u]>deep[edge[x].v]) tmp=edge[x].u;
			else tmp=edge[x].v;
			change(1,dfn[tmp],y);
		} else if(op==2){
			printf("%lld\n",min(Ask_LCA(x,y),min(Ask_LCA(x,edge[ring_pos].u)+Ask_LCA(y,edge[ring_pos].v),Ask_LCA(x,edge[ring_pos].v)+Ask_LCA(y,edge[ring_pos].u))+edge[ring_pos].w));
		}
	}
}