bzoj3282: Tree

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#include<cstdio>#include<cstring>#include<algorithm>#define ls c[x][0]#define rs c[x][1]using namespace std;const int maxn=300010;int n,m; struct LCT{    int c[maxn][2],fa[maxn],rev[maxn],sum[maxn],val[maxn];    bool isroot(int x){return (c[fa[x]][0]!=x)&&(c[fa[x]][1]!=x);}    int which(int x){return c[fa[x]][1]==x;}    void update(int x){sum[x]=sum[c[x][0]]^sum[c[x][1]]^val[x];}    void flip(int x){swap(c[x][0],c[x][1]),rev[x]^=1;}    void down(int x){if (rev[x]) flip(c[x][0]),flip(c[x][1]),rev[x]=0;}    void relax(int x){if (!isroot(x)) relax(fa[x]);down(x);}    void rotate(int x){        int y=fa[x],z=fa[y],nx=which(x),ny=which(y);        fa[c[x][!nx]]=y,c[y][nx]=c[x][!nx];        fa[x]=z;if (!isroot(y)) c[z][ny]=x;        fa[y]=x,c[x][!nx]=y;update(y);    }    void splay(int x){        relax(x);        while (!isroot(x)){            if (isroot(fa[x])) rotate(x);            else if (which(x)==which(fa[x])) rotate(fa[x]),rotate(x);            else rotate(x),rotate(x);        }        update(x);    }    void access(int x){for (int p=0;x;x=fa[x]) splay(x),fa[c[x][1]=p]=x,update(x),p=x;}    void makeroot(int x){access(x),splay(x),flip(x);}    void modify(int x,int v){val[x]=v,splay(x);}    int findroot(int x){access(x),splay(x);for (;c[x][0];x=c[x][0]);return x;}    void link(int a,int b){makeroot(a),fa[a]=b;}    void cut(int a,int b){makeroot(a),access(b),splay(b);if (c[b][0]==a) c[b][0]=fa[a]=0;}    int query(int a,int b){makeroot(a),access(b),splay(b);return sum[b];}}T; int main(){    scanf("%d%d",&n,&m);    for (int i=1,a;i<=n;i++) scanf("%d",&a),T.modify(i,a);    for (int i=1,op,a,b;i<=m;i++){        scanf("%d%d%d",&op,&a,&b);        if (op==0) printf("%d\n",T.query(a,b));        else if (op==1){if (!(T.findroot(a)==T.findroot(b))) T.link(a,b);}        else if (op==2) T.cut(a,b);        else T.modify(a,b);    }    return 0;}

又是一道tree...

题目大意：就是说的直接的bzoj2819：NIM，加边删边，单点修改。

思路：LCT维护链上的异或和，注意题目中的不保证。

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