树状数组模板

namespace BIT {
	int tr[/*数据范围 qwq*/], N;
	void init(int n) { N = n; for (int i = 1; i <= n; i ++) tr[i] = 0;}
	void update(int x, int y) { for (; x <= N; x += (x & (-x))) tr[x] += y;}
	int query(int x) { int res = 0; for (; x; x -= (x & (-x))) res += tr[x]; return res;}
} using namespace BIT;