區間XOR單點修改線段樹

struct segmenttree{
    int val[maxn*8];

    void maketree(int cur,int LB,int RB){
        if (LB == RB) val[cur] = arr[LB];
        else{
            maketree(cur*2,LB,mid);
            maketree(cur*2+1,mid+1,RB);
            val[cur] = val[cur*2] ^ val[cur*2+1];
        }
    }

    int query(int l,int r,int cur,int LB,int RB){
        if (l == LB and r == RB) return val[cur];
        else if (r <= mid) return query(l,r,cur*2,LB,mid);
        else if (l > mid) return query(l,r,cur*2+1,mid+1,RB);
        else return query(l,mid,cur*2,LB,mid) ^ query(mid+1,r,cur*2+1,mid+1,RB);
    }

    void mdf(int t,int v,int cur,int LB,int RB){
        if (LB == RB){
            val[cur] = v;
        }
        else{
            if (t <= mid) mdf(t,v,cur*2,LB,mid);
            else mdf(t,v,cur*2+1,mid+1,RB);
            val[cur] = val[cur*2] ^ val[cur*2+1];
        }
    }
};