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static const unsigned int divtab[244] = {
[1] = 0xffff + 1l,
[3] = 0x5555 + 1l,
[9] = 0x1c71 + 1l,
[27] = 0x097b + 1l,
[81] = 0x0329 + 1l,
[243] = 0x010d + 1l
};
#define FASTDIV(n, d) (((n) * divtab[d]) >> 16)
#define FASTMOD(n, d) ((n) - (d) * FASTDIV((n), (d)))
static const int A[] = {0, 1, -1};
static const int C[][3] = {{1, 1, -2}, {1, 1, -2}, {-2, 1, 1}};
int mastur2(const int i, const int x, const int y)
{
return i + A[x] * C[x][FASTMOD(FASTDIV(i, y), 3)] * y;
}
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