math/isqrt.cpp

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• Last update: 2021-06-21 15:24:20+09:00

Required by

• math/pell_equation.cpp

Code

ull Isqrt(ull const &x){
    ull ret = (ull)sqrtl(x);
    while(ret > 0 && ret*ret > x) --ret;
    while(x - ret*ret > 2*ret) ++ret;
    return ret;
}

#line 1 "math/isqrt.cpp"
ull Isqrt(ull const &x){
    ull ret = (ull)sqrtl(x);
    while(ret > 0 && ret*ret > x) --ret;
    while(x - ret*ret > 2*ret) ++ret;
    return ret;
}

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