algorithm/Math/Algebra/square_root.hpp

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• Last update: 2025-07-03 00:41:25+09:00
• Include: #include "algorithm/Math/Algebra/square_root.hpp"

Verified with

• verify/aoj-ITP1_10_A-isqrt.test.cpp

Code

#ifndef ALGORITHM_SQUARE_ROOT_HPP
#define ALGORITHM_SQUARE_ROOT_HPP 1

#include <cassert>
#include <cmath>

namespace algorithm {

// 平方根（ニュートン法）．
constexpr double sqrt(double x, double eps = 1e-10) {
    assert(x >= 0.0);
    double res = 1.0;
    while(true) {
        double tmp = (x / res + res) / 2;
        if(std::abs(tmp - res) < eps) break;
        res = tmp;
    }
    return res;
}

}  // namespace algorithm

#endif

#line 1 "algorithm/Math/Algebra/square_root.hpp"



#include <cassert>
#include <cmath>

namespace algorithm {

// 平方根（ニュートン法）．
constexpr double sqrt(double x, double eps = 1e-10) {
    assert(x >= 0.0);
    double res = 1.0;
    while(true) {
        double tmp = (x / res + res) / 2;
        if(std::abs(tmp - res) < eps) break;
        res = tmp;
    }
    return res;
}

}  // namespace algorithm

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