AP1 2017-10-11 Recursivitat 2

p1.py

# Floc de Koch   
# (vegeu https://en.wikipedia.org/wiki/Koch_snowflake)


import turtle           # https://docs.python.org/3.6/library/turtle.html

# pinta el segment bàsic de Koch _/\_ amb segments de llargada long i passos passes recursives
def figura(long, passos):
    if passos == 1:
        turtle.forward(long)
        turtle.left(60)
        turtle.forward(long)
        turtle.right(120)
        turtle.forward(long)
        turtle.left(60)
        turtle.forward(long)
    else:
        figura(long/3, passos-1)
        turtle.left(60)
        figura(long/3, passos-1)
        turtle.right(120)
        figura(long/3, passos-1)
        turtle.left(60)
        figura(long/3, passos-1)


# pinta el floc de Koch
def floc(long, passos):
    figura(long, passos)
    turtle.right(120)
    figura(long, passos)
    turtle.right(120)
    figura(long, passos)


floc(100, 3)
input()         # espera a tancar la finestra

p2.cc

// Torres de Hanoi


#include <iostream>
using namespace std;


// Mou n discos de ori a dst passant per aux.
void hanoi(int n, char ori, char dst, char aux) {
    if (n != 0) {
        hanoi(n - 1, ori, aux, dst);
        cout << "moure de " << ori << " a " << dst << endl;
        hanoi(n - 1, aux, dst, ori);
    }
}


int main() {
    int n;
    cin >> n;
    hanoi(n, 'A', 'C', 'B');
}

Tornant-ho a mirar: la funció figura() es pot simplificar més:

def figura(long, passos):
    if passos == 0:
        turtle.forward(long)
    else:
        figura(long/3, passos-1)
        turtle.left(60)
        figura(long/3, passos-1)
        turtle.right(120)
        figura(long/3, passos-1)
        turtle.left(60)
        figura(long/3, passos-1)