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/*
Copyright (C) 2015 Tommy Hofmann
Copyright (C) 2015 William Hart
This file is part of FLINT.
FLINT is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License (LGPL) as published
by the Free Software Foundation; either version 3 of the License, or
(at your option) any later version. See <https://www.gnu.org/licenses/>.
*/
#include "nmod.h"
#include "nmod_poly.h"
void nmod_poly_sub_ui(nmod_poly_t res, const nmod_poly_t poly, ulong c)
{
if (c >= poly->mod.n)
NMOD_RED(c, c, poly->mod);
if (poly->length == 0)
{
if (c == 0)
nmod_poly_zero(res);
else
{
nmod_poly_fit_length(res, 1);
nmod_poly_set_coeff_ui(res, 0, poly->mod.n - c);
_nmod_poly_set_length(res, 1);
}
}
else
{
nmod_poly_set(res, poly);
nmod_poly_set_coeff_ui(res, 0, nmod_sub(res->coeffs[0], c, poly->mod));
_nmod_poly_normalise(res);
}
}