打 codeforces 用的

我目前的级别大概只需要这些: ll q_pow(ll a, ll b, ll p) { ll ret = 1; for (; b; a = a * a % p, b >>= 1) if (b & 1) ret = ret * a % p; return ret; } ll inv(ll x, ll p) { return q_pow(x, p - 2, p); } int tree[MAXN]; inline int lowbit(int x) { return x & -x; } void insert(int pos, int k) { for (; pos <= N; po