diff --git a/README.md b/README.md index 987ce26..7cc69ec 100644 --- a/README.md +++ b/README.md @@ -8,6 +8,7 @@ | ChudnovskyAlgorithm | 楚德诺夫斯基算法 | [chudnovsky-algorithm](https://hatter.ink/static/resource/muboard/?id=chudnovsky-algorithm&version=latest&full=1) | | EulerNumber | 欧拉数 | [eulers-number](https://hatter.ink/static/resource/muboard/?id=eulers-number&version=latest&full=1) | | EulerTheorem | 欧拉定理 | [euler-theorem](https://hatter.ink/static/resource/muboard/?id=euler-theorem&version=latest&full=1) | +| FibonacciSequence | 斐波那契数列 | [fibonacci-sequence](https://hatter.ink/static/resource/muboard/?id=fibonacci-sequence&version=latest&full=1) | | LeibnizFormula | $\pi$ 的莱布尼茨公式 | [leibniz-formula](https://hatter.ink/static/resource/muboard/?id=leibniz-formula&version=1) | | ModularInv | 求乘法逆元【扩展欧几里得法】 | - | | Prime | 试除法 | - | diff --git a/src/main/java/me/hatter/math/FibonacciSequence.java b/src/main/java/me/hatter/math/FibonacciSequence.java new file mode 100644 index 0000000..d328766 --- /dev/null +++ b/src/main/java/me/hatter/math/FibonacciSequence.java @@ -0,0 +1,35 @@ +package me.hatter.math; + +import me.hatter.math.util.MathUtil; + +import java.math.BigDecimal; +import java.math.BigInteger; +import java.math.RoundingMode; +import java.util.ArrayList; +import java.util.List; + +public class FibonacciSequence { + static final BigDecimal SQRT5 = MathUtil.sqrt(BigDecimal.valueOf(5), 100); + + public static void main(String[] args) { + List nums = new ArrayList<>(); + List num2s = new ArrayList<>(); + for (int i = 0; i < 20; i++) { + nums.add(fn(i)); + num2s.add(fn2(i)); + } + System.out.println(nums); + System.out.println(num2s); + } + + public static BigInteger fn(int n) { + BigDecimal a = BigDecimal.ONE.add(SQRT5).divide(BigDecimal.valueOf(2), 100, RoundingMode.HALF_UP); + BigDecimal b = BigDecimal.ONE.subtract(SQRT5).divide(BigDecimal.valueOf(2), 100, RoundingMode.HALF_UP); + return a.pow(n).subtract(b.pow(n)).divide(SQRT5, 0, RoundingMode.HALF_UP).toBigInteger(); + } + + public static BigInteger fn2(int n) { + BigDecimal a = BigDecimal.ONE.add(SQRT5).divide(BigDecimal.valueOf(2), 100, RoundingMode.HALF_UP); + return a.pow(n).divide(SQRT5, 0, RoundingMode.HALF_UP).toBigInteger(); + } +}