1#include <stdint.h>
2#include <stdlib.h>
3
4static uint64_t seed;
5
6void srand(unsigned s) {
7    seed = s - 1;
8}
9
10int rand(void) {
11    seed = 6364136223846793005ULL * seed + 1;
12    return seed >> 33;
13}
14