"Manual Open Stack" "Dfs sequence" "Tree Array" "Tarjan" bzoj2819 Nim

Consider the point query of the tree array interval modification (which affects only the answers to its subtree), and each point records its weight-to-value XOR on the root path.

Answer when query (L) ^query (R) ^a[lca].

This method avoids tree chain splits when asked on a tree that supports interval addition and subtraction.

May explode stack, consider manual open stack. (Eh eh Tarjan pretreatment LCA when did not manually open the stack?) Don't mind ^_^)

It's not actually going to explode.

#include <cstdio> #include <stack> #include <algorithm> #include <queue> #include <cmath> #include <vector>using namespace std; #define N 500001typedef pair<int,int> point;vector<point>ask[n ];int N,a[n],b[n],m,ancestor[n];int En,first[n],next[n<<1],v[n<<1];int FA[N],rank[N],lcas[N];void Addedge (const int &u,const int &v) {v[++en]=v;next[en]=first[u];first[u]=en;} int findroot (int x) {return fa[x]==x?x:findroot (fa[x]);}    void Union (int x,int y) {int u=findroot (x);    int V=findroot (y);        if (Rank[u]<rank[v]) fa[u]=v;else {fa[v]=u;      if (Rank[u]==rank[v]) ++rank[u];    }}bool vis[n];void LCA (int u,int Fa) {ancestor[u]=u;for (int i=first[u];i;i=next[i]) if (V[I]!=FA) {LCA (v[i],u);          Union (U,v[i]);    Ancestor[findroot (U)]=u; }vis[u]=1;for (int i=0;i<ask[u].size (); i++) if (Vis[ask[u][i].first]) lcas[ask[u][i].second]=ancestor[findroot ( Ask[u][i].first)];} Stack<int>st;queue<int>q;int tot,lS[n],rs[n],root=1;void Dfs () {st.push (1);  Ls[1]=++tot;b[1]=a[1];while (!st.empty ()) {int u=st.top (); bool flag=0; for (int i=first[u];i;i=next[i]) if (!        Ls[v[i]]) {ls[v[i]]=++tot;        B[v[i]]= (A[v[i]]^b[u]);        St.push (V[i]);        First[u]=next[i];        flag=1;      Break    } if (!flag) {rs[u]=tot;    St.pop (); }}}int d[n];void add_node (int p,const int &v) {for (;p <=n;p+= (-P)) p&;} void Add_range (const int &AMP;L,CONST int &r,const int &v) {Add_node (l,v), if (r!=n) Add_node (r+1,v);} int query (int p) {int res=0;for (;p; p-= (-P)) Res^=d[p];return res;} int a[n],b[n];  Char Op[n][2];int main () {int x,y;scanf ("%d", &n), for (int i=1;i<=n;++i) {fa[i]=i;  scanf ("%d", &a[i]);  }for (int i=1;i<n;++i) {scanf ("%d%d", &x,&y);  Addedge (x, y);  Addedge (Y,X); }SCANF ("%d", &m), for (int i=1;i<=m;++i) {scanf ("%s%d%d", Op[i],&a[i],&b[i]), if (op[i][0]== ' Q ') {ask[a[  I]].push_back (Make_pair (b[i],i)); Ask[b[i]].  Push_back (Make_pair (a[i],i)); }}LCA (1,0);d FS (), for (int i=1;i<=n;++i) Add_range (Ls[i],ls[i],b[i]), for (int i=1;i<=m;++i) if (op[i][0]== ' Q ') Puts ((query (Ls[a[i]) ^query (Ls[b[i]]) ^a[lcas[i]])? "  Yes ":" No ");    else {add_range (ls[a[i]],rs[a[i]],a[a[i]]^b[i]);    A[a[i]]=b[i]; }return 0;}

"Manual Open Stack" "Dfs Order" "Tree Array" "Tarjan" bzoj2819 Nim