生成随机数
#include <random>
mt19937_64 rnd(random_device{}());
uniform_int_distribution<long long> dist(0, ULLONG_MAX);
long long r = dist(rnd);
#include <random>
mt19937_64 rnd(random_device{}());
uniform_int_distribution<long long> dist(0, ULLONG_MAX);
long long r = dist(rnd);