1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152
| #include <bits/stdc++.h> #define MAXN 2000005 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; } vector<int>G[MAXN]; inline void AddEdge(int u,int v){ G[u].push_back(v); } 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]; if (v!=father){ dep[v]=dep[u]+1; dfs1(v,u); sz[u]+=sz[v]; if (sz[big[u]]<sz[v]) big[u]=v; } } } int seq[MAXN],cnt; int alb[MAXN]; void dfs2(int u,int t){ alb[seq[u]=++cnt]=u; top[u]=t; if (big[u]) dfs2(big[u],t); for (register int i=0;i<G[u].size();++i){ int v=G[u][i]; if (v!=fa[u]&&v!=big[u]){ dfs2(v,v); } } } namespace SegmentTree{ struct node{ int l,r; int val,tag; inline int len(){ return r-l+1; } }tree[MAXN<<2]; #define lc i<<1 #define rc i<<1|1 inline void pushup(int i){ tree[i].val=tree[lc].val+tree[rc].val; } inline void Change(int i,int val){ tree[i].val+=val*tree[i].len(); tree[i].tag+=val; } inline void pushdown(int i){ if (tree[i].tag){ Change(lc,tree[i].tag); Change(rc,tree[i].tag); tree[i].tag=0; } } void Build(int i,int l,int r){ tree[i].l=l,tree[i].r=r; if (l==r) { tree[i].val=0; 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].val; } pushdown(i); int mid=(tree[i].l+tree[i].r)>>1,ans=0; if (L<=mid) ans=max(ans,Query(lc,L,R)); if (mid<R) ans=max(ans,Query(rc,L,R)); return ans; } void Update(int i,int L,int R){ if (L<=tree[i].l&&tree[i].r<=R){ Change(i,1); return ; } int mid=(tree[i].l+tree[i].r)>>1; pushdown(i); if (L<=mid) Update(lc,L,R); if (mid<R) Update(rc,L,R); pushup(i); } } using namespace SegmentTree; inline int Query_Chain(int u,int v){ int ans=0; while (top[u]!=top[v]){ if (dep[top[u]]<dep[top[v]]){ swap(u,v); } ans+=Query(1,seq[top[u]],seq[u]); u=fa[top[u]]; } if (dep[u]>dep[v]) swap(u,v); return ans+Query(1,seq[u]+1,seq[v]); } inline void Update_Chain(int u,int v){ while (top[u]!=top[v]){ if (dep[top[u]]<dep[top[v]]){ swap(u,v); } Update(1,seq[top[u]],seq[u]); u=fa[top[u]]; } if (dep[u]>dep[v]) swap(u,v); Update(1,seq[u]+1,seq[v]); } inline void Init(){ dfs1(1,0); dfs2(1,1); } int main(){ int n=read(),m=read(); for (register int i=1;i<n;++i){ int u=read(),v=read(); AddEdge(u,v); AddEdge(v,u); } Init(); Build(1,1,n); while (m--){ char ch[2]; scanf("%s",ch); int u=read(),v=read(); if (ch[0]=='Q') { printf("%d\n",Query_Chain(u,v)); } else if (ch[0]=='P'){ Update_Chain(u,v); } } }
|