MATLAB: Hanoi Tower´s problem using recursion

Question

Hello i´m developping a program to solve the hanoi tower problem using a recoursive function but it doesn´t seens to work.I´m going to put the code that i have writen and going to explain the ideia and the data matrixes.

Main program:

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N=5;
torre_final =1;
vec_movimentos = zeros ((power(2,N)-1),4);
for i=1:size(vec_movimentos,1)
    vec_movimentos(i,1)=i;
end
tabuleiro = zeros(N,3);
tabuleiro(:,1)=1:N;
n_jogada =1;
[vec_movimentos] = hanoi_code(N,torre_final,vec_movimentos,n_jogada,tabuleiro);

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hanoi_code is my recursive function and the matrix 'tabuleiro' represents the 3 tower´s with N disk. 'vec_movimentos' is a matrix that describes the moves that the user has to do in order to resolve the problem. The first column of 'vec_movimentos' is the counter of the number of moves; the second column is what piece the user has to move; the third column is the inicial tower that the piece is located at; the forth column is the final cloumn that the piece is going to be move to;'torre_final' is a variable with 2 possible values: 1 or 2. If torre_final = 1 then the solution is going to be formed in the center tower; if torre_final=2 then the solution is going to exist in the final right tower

hanoi_code:

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function [vec_movimentos] =hanoi_code(N,torre_final,vec_movimentos,n_jogada,tabuleiro)
%torre_final == 1 consiste no deslocamento para a torre 1 posição à direita
%torre_final == 2 consiste no deslocamento para a torre 2 posições à
%direita
 if N > 0;
hanoi_code(N-1,torre_final,vec_movimentos,n_jogada,tabuleiro);
shift(N,torre_final,vec_movimentos,n_jogada,tabuleiro);
hanoi_code(N-1,torre_final,vec_movimentos,n_jogada,tabuleiro);
 else
 return;
end

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we have here the recursive code ,'n_jogada' indicates what the current move is.

shift:

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function [vec_movimentos] =shift(N,torre_final,vec_movimentos,n_jogada,tabuleiro)
vec_movimentos(n_jogada,2)=N;
[inicio,fim]= game(N,tabuleiro,torre_final);
vec_movimentos(n_jogada,3)=inicio;
vec_movimentos(n_jogada,4)=fim;
n_jogada =n_jogada+1;
end

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It´s not necessary to display the game code because the program doesn´t get there and i have already test this part of the code and it seens to work.

My main problem is that the recursion seens not to work. When i run the program the 'vec_movimentos' remains the same , and the 'tabuleiro' also remains in the original configuration. The 'n_jogadas' that should = 31 , is equal =1. 31 because the numbers of moves if 2^(N)-1 , and N=5. Any ideia what´s the problem? What´s wrong with the recursion part?

Thank you in advance

Answer 1

Remember that calling

hanoi_code(N-1,torre_final,vec_movimentos,n_jogada,tabuleiro);

computes a value by calling hanoi_code, and then discards the value because you did not assign it to a variable and the semi-colon says not to bother to print the result either.