快速幂优化

typedef long long ll;ll quick_mul(ll a, ll b, ll m) {//快速乘法运算 ll ans = 0;while(b) {if(b&1) ans = (ans + a) % m;a = (a + a) % m;b>>=1;}return ans;}ll quick_pow(ll a, ll b, ll m) {//快速幂运算 ll ans = 1;while(b) {if(b&1)ans = quick_mul(ans , a , m);a = quick_mul(a , a , m);b>>=1;}return ans;}