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PO8-Queens snippet
 

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    <p>I have currently learning backtracking and got stuck on the 8-queen problem, I am using a 8x8 matrix and I think I've got some problems regarding the matrix passing to functions, any help would be highly apreciated.I wouldn't mind if anyone would bring any optimisation to the code, thanks.</p> <p>here is my code.</p> <pre><code>#include &lt;stdio.h&gt; #include &lt;stdlib.h&gt; #define MAX 7 //void azzera(int **mat); void posiziona(int **mat, int r,int c); void stampa(int **mat); int in_scacchi(int **mat,int r ,int c); int main(int argc, char *argv[]) { int i=0,j=0; int **mat=(int **)malloc(sizeof(int *)*MAX); for(i=0;i&lt;=MAX;i++){ mat[i]=(int *)malloc(MAX*sizeof(int)); for(j=0;j&lt;=MAX;j++){ mat[i][j]=-1; } } printf("insert pos of the first queen on the first row (1-8) :"); scanf("%d",&amp;i); i-=1; mat[0][i]=1; posiziona(mat,1,0); stampa(mat); system("PAUSE"); return 0; } /*void azzera(int **mat){ int i=0,j=0; for(i=0;i&lt;=MAX;i++){ for(j=0;j&lt;=MAX;j++){ mat[i][j]=-1; } } }*/ void stampa(int **mat){ int i,j; for(i=0;i&lt;=MAX;i++){ for(j=0;j&lt;=MAX;j++){ printf(" %d",mat[i][j]); } printf("\n"); } } void posiziona(int **mat, int r,int c){ int i=0,riga=1,flag_col=-1,flag_riga=-1; if(riga&lt;=7&amp;&amp;flag_riga!=1){ if(flag_riga==1){ flag_riga=-1; posiziona(mat,r+1,0); } else if(in_scacchi(mat,r,c)==1){ if(c==MAX) posiziona(mat,r-1,0); posiziona(mat,r,c+1); } else{ flag_riga=1; } } } int in_scacchi(int **mat,int r ,int c){ int i,j,k,m; int flag=0; //col for(i=0;i&lt;r;i++){ for(j=0;j&lt;=c;j++){ if(((mat[i][j]==1)&amp;&amp;(c==j))) return 1; } } //diag \ for(i=0;i&lt;MAX-r;i++){ for(j=0;j&lt;=MAX-c;j++){ if(mat[MAX-r-i][MAX-c-j]==1) return 1; } } //antidiag for(i=r+1;i&lt;=MAX;i++){ for(j=c+1;j&lt;=MAX;j++){ if(mat[r-i][c+j]==1) { return 1; } } } return 0; } </code></pre>
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    1. CO**8** -Queens <-> #define MAX **7** doesn't seem right.
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    2. CONote: 8-Queens problem can be solved with out passing matrix to recursion function
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    3. CO@user786653 - Erm, it does considering computers generally think of series as being zero based
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