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| #include <bits/stdc++.h> #define MAXN 2000005 #define HA 19260817 #define INF 0x3f3f3f3f using namespace std; inline int read(){ int 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<<3)+(x<<1)+(ch^'0'); ch=getchar(); } return x*f; } struct Edge{ int to,len; }; vector<Edge>G[MAXN]; inline void AddEdge(int u,int v,int w){ G[u].push_back(Edge{v,w}); } int sz[MAXN],big[MAXN],fa[MAXN],top[MAXN],dep[MAXN],tofa[MAXN]; void dfs1(int u,int father){ fa[u]=father;sz[u]=1; for (register int i=0;i<G[u].size();++i){ int v=G[u][i].to; if (v!=father){ dep[v]=dep[u]+1; tofa[v]=G[u][i].len; dfs1(v,u); sz[u]+=sz[v]; if (sz[big[u]]<sz[v]) big[u]=v; } } } int ql[MAXN],alb[MAXN],cnt; void dfs2(int u,int t){ alb[ql[u]=++cnt]=u; top[u]=t; if (big[u]) dfs2(big[u],t); for (register int i=0;i<(int)G[u].size();++i){ int v=G[u][i].to; if (v!=fa[u]&&v!=big[u]){ dfs2(v,v); } } } namespace SegmentTree{ struct node{ int l,r; int maxn,tag,cotag; }tree[MAXN<<2]; #define lc i<<1 #define rc i<<1|1 inline void pushup(int i){ tree[i].maxn=max(tree[lc].maxn,tree[rc].maxn); } inline void Add(int i,int val){ tree[i].maxn+=val; tree[i].tag+=val; } inline void Cover(int i,int val){ tree[i].maxn=val; tree[i].cotag=val; tree[i].tag=0; } inline void pushdown(int i){ if (tree[i].cotag!=HA){ Cover(lc,tree[i].cotag); Cover(rc,tree[i].cotag); tree[i].cotag=HA; } if (tree[i].tag){ Add(lc,tree[i].tag); Add(rc,tree[i].tag); tree[i].tag=0; } } void Build(int i,int l,int r){ tree[i].l=l,tree[i].r=r; tree[i].cotag=HA,tree[i].tag=0; if (l==r){ tree[i].maxn=tofa[alb[l]]; return ; } int mid=(l+r)>>1; Build(lc,l,mid); Build(rc,mid+1,r); pushup(i); } int Query(int i,int L,int R){ if (L<=tree[i].l&&tree[i].r<=R){ return tree[i].maxn; } int mid=(tree[i].l+tree[i].r)>>1,ans=-INF; pushdown(i); if (L<=mid) ans=max(ans,Query(lc,L,R)); if (mid<R) ans=max(ans,Query(rc,L,R)); return ans; } void CoverInterval(int i,int L,int R,int val){ if (L<=tree[i].l&&tree[i].r<=R){ Cover(i,val); return ; } int mid=(tree[i].l+tree[i].r)>>1; pushdown(i); if (L<=mid) CoverInterval(lc,L,R,val); if (mid<R) CoverInterval(rc,L,R,val); pushup(i); } void AddInterval(int i,int L,int R,int val){ if (L<=tree[i].l&&tree[i].r<=R){ Add(i,val); return ; } int mid=(tree[i].l+tree[i].r)>>1; pushdown(i); if (L<=mid) AddInterval(lc,L,R,val); if (mid<R) AddInterval(rc,L,R,val); pushup(i); } } using namespace SegmentTree; inline void Add_Chain(int u,int v,int w){ while (top[u]!=top[v]){ if (dep[top[u]]<dep[top[v]]){ swap(u,v); } AddInterval(1,ql[top[u]],ql[u],w); u=fa[top[u]]; } if (dep[u]>dep[v]) swap(u,v); AddInterval(1,ql[u]+1,ql[v],w); } inline void Cover_Chain(int u,int v,int w){ while (top[u]!=top[v]){ if (dep[top[u]]<dep[top[v]]){ swap(u,v); } CoverInterval(1,ql[top[u]],ql[u],w); u=fa[top[u]]; } if (dep[u]>dep[v]) swap(u,v); CoverInterval(1,ql[u]+1,ql[v],w); } inline int Query_Chain(int u,int v){ int ans=-INF; while (top[u]!=top[v]){ if (dep[top[u]]<dep[top[v]]){ swap(u,v); } ans=max(ans,Query(1,ql[top[u]],ql[u])); u=fa[top[u]]; } if (dep[u]>dep[v]) swap(u,v); return max(ans,Query(1,ql[u]+1,ql[v])); } int U[MAXN],V[MAXN]; inline void Init(){ dfs1(1,0); dfs2(1,1); } int main(){ int n=read(); for (register int i=1;i<n;++i){ int u=read(),v=read(),w=read(); AddEdge(u,v,w); AddEdge(v,u,w); U[i]=u,V[i]=v; } Init(); Build(1,1,n); while (true){ char ch[10]; scanf("%s",ch); if (ch[0]=='C'&&ch[1]=='h'){ int k=read(),w=read(); Cover_Chain(U[k],V[k],w); } else if (ch[0]=='C'&&ch[1]=='o'){ int u=read(),v=read(),w=read(); Cover_Chain(u,v,w); } else if (ch[0]=='A'){ int u=read(),v=read(),w=read(); Add_Chain(u,v,w); } else if (ch[0]=='M'){ int u=read(),v=read(); printf("%d\n",Query_Chain(u,v)); } else { break; } } }
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