[Stencil] BIT Tree-like array

Tree-like Array (BIT)

The tree-like array is not only the function of interval and sany, but also can be used to calculate the maximum or special value between the two, (its query and insert operations are O (LOGN) level);

Its greatest advantage is simple and easy to write, easy to achieve;

Defined:

// * Array size #define Bitsz (+)//int Bit[bitsz]

Single-point add function:

void Addbit (int k,int  val) {    while (k<=bitsz) {        Bit[k]+ = val ;        K+=k&-k;    }    return ;     }

query [1,k] for intervals and functions:

int Querybit (int  k) {    int sum=0;      while (k>0) {        sum+ =Bit[k];        K-=k&-k;    }    return sum;     }

[Stencil] BIT Tree-like array