Algorithm

Project Euler 25. 1000-digit Fibonacci number
Simple - linear

import java.math.BigInteger;

public class Linear {

    public static void main(String[] args) {
        int i = 1;
        BigInteger fi = BigInteger.ONE, fj = BigInteger.ONE;
        while (fi.toString().length() < 1000) {
            BigInteger fk = fi.add(fj);
            fi = fj;
            fj = fk;
            ++i;
        }
        System.out.println(i);
    }
}

Jump - log linear

import java.math.BigInteger;
import java.util.HashMap;

public class LogLinear {

    public static void main(String[] args) {
        HashMap<Integer, BigInteger> m = new HashMap<>();
        m.put(1, BigInteger.ONE);
        m.put(2, BigInteger.ONE);
        m.put(3, BigInteger.valueOf(2));

        int i = 2;
        while (m.get(i).toString().length() < 1000) {
            m.put(2*i - 1, m.get(i - 1).multiply(m.get(i - 1)).add(m.get(i).multiply(m.get(i))));
            m.put(2*i + 1, m.get(i + 1).multiply(m.get(i + 1)).add(m.get(i).multiply(m.get(i))));
            m.put(2*i, m.get(2*i + 1).subtract(m.get(2*i - 1)));
            i = 2*i;
        }
        i = i/2;

        BigInteger fi = m.get(i), fj = m.get(i + 1);
        while (fi.toString().length() < 1000) {
            BigInteger fk = fi.add(fj);
            fi = fj;
            fj = fk;
            ++i;
        }
        System.out.println(i);
    }
}

Review

Understanding Zero-knowledge proofs through illustrated examples

Properties of zero-knowledge proof system

• soundness
• completeness
• zero-knowledge

sometimes a zero-knowledge proof system is only statistical

Tip

Code reuse approaches

• Inheritance
• Composition
• Mixin
• Trait

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Tacit Knowledge

The software industry overvalues comprehension and explanation.
Knowing how to program is very different from explaining your program, or even understanding the program you just finished writing.