【树状数组】树状数组一维二维模板

以下模板都是点更新，区间查询，如果是区间更新点查询，只需将利用lowbit的循环方向倒过来

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一维：

inline int lowbit(int x){    return x & -x;}void add(int x, int val){    for(int i = x; i <= n; i += lowbit(i)) C[i] += val;}int sum(int x){    int ret = 0;    for(int i = x; i > 0; i -= lowbit(i)) ret += C[i];    return ret;}

二维：

inline int lowbit(int x){    return x & -x;}void add(int x, int y, int val){    for(int i = x; i <= n; i+=lowbit(i)) {        for(int j = y; j <= n; j+=lowbit(j)) {            C[i][j] += val;        }    }}int sum(int x, int y){    int ret = 0;    for(int i = x; i > 0; i-=lowbit(i)) {        for(int j = y; j > 0; j-=lowbit(j)) {            ret += C[i][j];        }    }    return ret;}