随机哈希

使用的随机算法

struct custom_hash {
    static u64 splitmix64(u64 x) {
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    u64 operator()(u64 x) const {
        static const u64 SEED =
            std::chrono::high_resolution_clock::now().time_since_epoch().count();
        return splitmix64(x + SEED);
    }
};