luogu P3950 部落冲突

嘟嘟嘟

树剖板子题。

 #include<cstdio>
 #include<iostream>
 #include<algorithm>
 #include<cmath>
 #include<cstring>
 #include<cstdlib>
 #include<cctype>
 #include<stack>
 #include<queue>
 #include<vector>
 using namespace std;
 #define enter puts("")
 #define space putchar(' ')
 #define Mem(a, x) memset(a, x, sizeof(a))
 #define rg register
 typedef long long ll;
 typedef double db;
 const int INF = 0x3f3f3f3f;
 const db eps = 1e-;
 const int maxn = 3e5 + ;
 inline ll read()
 {
   ll ans = ;
   char ch = getchar(), las = ' ';
   while(!isdigit(ch)) las = ch, ch = getchar();
   while(isdigit(ch)) ans = ans *  + ch - '', ch = getchar();
   if(las == '-') ans = -ans;
   return ans;
 }
 inline void write(ll x)
 {
   if(x < ) putchar('-'), x = -x;
   if(x >= ) write(x / );
   putchar(x %  + '');
 }

 int n, m;
 struct Edge
 {
   int to, nxt;
 }e[maxn << ];
 int head[maxn], ecnt = ;
 void addEdge(int x, int y)
 {
   e[++ecnt].to = y;
   e[ecnt].nxt = head[x];
   head[x] = ecnt;
 }

 int dep[maxn], fa[maxn], siz[maxn], son[maxn];
 void dfs1(int now, int f)
 {
   siz[now] = ;
   for(int i = head[now]; i; i = e[i].nxt)
     {
       if(e[i].to == f) continue;
       dep[e[i].to] = dep[now] + ;
       fa[e[i].to] = now;
       dfs1(e[i].to, now);
       siz[now] += siz[e[i].to];
       if(!son[now] || siz[e[i].to] > siz[son[now]]) son[now] = e[i].to;
     }
 }
 int top[maxn], dfsx[maxn], cnt = ;
 void dfs2(int now, int f)
 {
   dfsx[now] = ++cnt;
   if(son[now])
     {
       top[son[now]] = top[now];
       dfs2(son[now], now);
     }
   for(int i = head[now]; i; i = e[i].nxt)
     {
       if(e[i].to == f || e[i].to == son[now]) continue;
       top[e[i].to] = e[i].to;
       dfs2(e[i].to, now);
     }
 }

 int l[maxn << ], r[maxn << ], sum[maxn << ];
 void build(int L, int R, int now)
 {
   l[now] = L; r[now] = R;
   if(L == R) return;
   int mid = (L + R) >> ;
   build(L, mid, now << );
   build(mid + , R, now <<  | );
 }
 void update(int idx, int now)
 {
   if(l[now] == r[now]) {sum[now] ^= ; return;}
   int mid = (l[now] + r[now]) >> ;
   if(idx <= mid) update(idx, now << );
   else update(idx, now <<  | );
   sum[now] = sum[now << ] + sum[now <<  | ];
 }
 bool query(int L, int R, int now)
 {
   if(L == l[now] && R == r[now]) return sum[now];
   int mid = (l[now] + r[now]) >> ;
   if(R <= mid) return query(L, R, now << );
   else if(L > mid) return query(L, R, now <<  | );
   else return query(L, mid, now << ) | query(mid + , R, now <<  | );
 }

 bool query_path(int x, int y)
 {
   while(top[x] != top[y])
     {
       if(dep[top[x]] < dep[top[y]]) swap(x, y);
       if(query(dfsx[top[x]], dfsx[x], )) return ;
       x = fa[top[x]];
     }
   if(dfsx[x] > dfsx[y]) swap(x, y);
   if(x == y) return ;
   return query(dfsx[x] + , dfsx[y], ) ^ ;
 }

 int war[maxn], wcnt = ;
 char c[];

 int main()
 {
   n = read(); m = read();
   for(int i = ; i < n; ++i)
     {
       int x = read(), y = read();
       addEdge(x, y); addEdge(y, x);
     }
   dfs1(, ); top[] = ; dfs2(, );
   build(, cnt, );
   for(int i = ; i <= m; ++i)
     {
       scanf("%s", c);
       if(c[] == 'Q')
     {
       int x = read(), y = read();
       printf("%s\n", query_path(x, y) ? "Yes" : "No");
     }
       else if(c[] == 'C')
     {
       int x = read(), y = read();
       if(dfsx[x] < dfsx[y]) swap(x, y);
       war[++wcnt] = x;
       update(dfsx[x], );
     }
       else
     {
       int x = read();
       update(dfsx[war[x]], );
     }
     }
   return ;
 }