树状数组模板

更新值和区间求和，以及lowbit

int N,c[50005];int lowbit(int i){    return i&(-i);}void add(int i,int value){    while(i <= N){        c[i] += value;        i += lowbit(i);    }}int sum(int i){    int sum = 0;    while(i > 0){        sum += c[i];        i -= lowbit(i);    }    return sum;}