树状数组 模板

int lowbit(int t){return t&(-t);}void change(int pos , int num,int n)  //修改{    while (pos<=n)     {        tree[pos] += num;        pos += lowbit(pos);    }}int ask(int end)//查询{   int sum = 0;  while(end > 0)   {       sum += tree[end];   end -= lowbit(end);   }  return sum;}