ACM模版

一维

/* * INIT: ar[]置为0; * CALL: add(i, v): 将i点的值加v; sum(i): 求[1, i]的和; */
#define typev int // type of res

const int N = 1010;

typev ar[N];        // index: 1 ~ N

int lowb(int t)
{
    return t & (-t);
}

void add(int i, typev v)
{
    for (; i < N; ar[i] += v, i += lowb(i));
    return ;
}

typev sum(int i)
{
    typev s = 0;
    for (; i > 0; s += ar[i], i -= lowb(i));
    return s;
}

二维

/* * INIT: c[][]置为0; Row,Col要赋初值 */
const int N = 10000;

int c[N][N];
int Row, Col;

inline int Lowbit(const int &x)
{   // x > 0
    return x & (-x);
}

int Sum(int i, int j)
{
    int tempj, sum = 0;
    while (i > 0)
    {
        tempj = j;
        while (tempj > 0)
        {
            sum += c[i][tempj];
            tempj -= Lowbit(tempj);
        }
        i -= Lowbit(i);
    }
    return sum;
}

void Update(int i, int j, int num)
{
    int tempj;
    while (i <= Row)
    {
        tempj = j;
        while (tempj <= Col)
        {
            c[i][tempj] += num;
            tempj += Lowbit(tempj);
        }
        i += Lowbit(i);
    }
    return ;
}