******** fig10.53 **********

	/* Compute All-Shortest Paths */
	/* A[] contains the adjacency matrix with A[i][i] presumed to be zero */
	/* D[] contains the values of the shortest path */
	/* |V| is the number of vertices */
	/* A negative cycle exists iff d[i][j] is set to a negative value at line 9 */
	/* Actual path can be computed via another procedure using path[] */
	/* All arrays are indexed starting at 0 */

	void
	all_pairs( two_d_array A, two_d_array D, two_d_array path )
	{
		int i, j, k;

/*1*/		for( i=0; i < |V|; i++ )	/* Initialize D and path */
/*2*/			for( j=0; j < |V|; j++ )
			{
/*3*/				D[i][j] = A[i][j];
/*4*/				path[i][j] = NOT_A_VERTEX;
			}
/*5*/		for( k=0; k < |V|; k++ )	/* Consider each vertex as an intermediate */
/*6*/			for( i=0; i < |V|; i++ )
/*7*/				for( j=0; j < |V|; j ++ )
/*8*/					if( d[i][k] + d[k][j] < d[i][j] )	/*update min */
					{
/*9*/						d[i][j] = d[i][k] + d[k][j];
/*10*/						path[i][j] = k;
					}
	}