@@ -0,0 +1,527 @@
+package com.matao.fundamentals.exercises;%0A%0Aimport edu.princeton.cs.algs4.StdOut;%0A%0A/**%0A * Created by matao on 2018/8/22.%0A * %3Cp%3E%0A * Write a recursive static method that computes the value of ln(N!)%0A */%0Apublic class Ex_1_1_20 %7B%0A%0A    // ln(N!) == ln(N * (N-1)!) == lnN + ln((N-1)!)%0A    public static double lnFactorial(int N) %7B%0A        if (N == 0) %7B%0A            return 0;%0A        %7D%0A        return Math.log(N) + lnFactorial(N - 1);%0A    %7D%0A%0A    public static void main(String%5B%5D args) %7B%0A        StdOut.println(lnFactorial(3));%0A    %7D%0A%7D%0A

add solution to exercise 1.1.20