int solve(){
/* need factorial to calculate size of tables */
int* fact = factorial(SIZE);
/* maximum size of a hash of size SIZE*/
int max_index = fact[SIZE] - 1;
/* tables to store hashes of permutations */
char* table_now = calloc(max_index, sizeof(char));
char* table_next = calloc(max_index, sizeof(char));
/* table pointer for swapping */
char* table_temp = NULL;
/* table index */
unsigned int ti;
/* how deep we are */
int depth;
/* set the initial configuration, an ascending sort of consecutive integers 1 .. SIZE */
table_now[0] = 1;
/* perform all possible swaps from positions in "table_now" */
/* record these swapped positions in table_next */
for(depth = 0 ; depth < DEPTH; depth++){
/* iterate over generation, build next generation */
for(ti = 0; ti < max_index; ti++){
/* if the position was reached last time */
if(table_now[ti] == 1){
/* rebuild the sequence from the hash */
int* sequence = inv_lex_rank(ti);
int swaps;
for(swaps = 0; swaps < SIZE - 1; swaps++){
/* swap it */
swap(sequence, swaps);
/* set the resulting sequence in the next generation */
table_next[lex_rank(sequence)] = 1;
/* swap it back */
swap(sequence, swaps);
}/* end for (swaps) */
/* we're done with this sequence */
free(sequence);
}/* end if */
}/* end for (ti) */
/* swap tables */
table_temp = table_next;
table_next = table_now;
table_now = table_temp;
/* clear out next */
memset(table_next, 0, fact[SIZE] - 1);
}/* end for (depth) */
/* now count the set bits */
int answer = 0;
for(ti = 0; ti < max_index; ti++){
if(table_now[ti] > 0){
answer++;
}
}
printf("%d\n", answer);
free(table_now);
free(table_next);
return answer;
}
/*test the inverse functions on each other */
void test_lex_rank(){
int x;
for(x = 0; x < 5040; x++){
if(lex_rank(inv_lex_rank(x)) != x){
printf("%d doesn't work\n", x);
prar(inv_lex_rank(x));
fflush(stdout);
}
}
}
/* Map any node to its I/O node */
int io_node(const int node){
int i,j,k;
/* Get the machine coordinates for the specified node */
lex_coords(io_node_coords, 4, machine_dimensions, node);
/* Round the node coordinates down to get the io_node coordinate */
for(i = 0; i < 4; i++)
io_node_coords[i] = nodes_per_ionode[i] *
(io_node_coords[i]/nodes_per_ionode[i]);
/* Return the linearized machine coordinates of the I/O node */
return (int)lex_rank(io_node_coords, 4, machine_dimensions);
}
/* Map any node to its I/O node */
int io_node(const int node){
int i;
int io_node_coords[4];
/* If we don't have I/O partitions, each node does its own I/O */
if(ionodegeomvals == NULL)
return node;
/* Get the machine coordinates for the specified node */
lex_coords(io_node_coords, 4, dim_mach, node);
/* Round the node coordinates down to get the io_node coordinate */
for(i = 0; i < 4; i++)
io_node_coords[i] = nodes_per_ionode[i] *
(io_node_coords[i]/nodes_per_ionode[i]);
/* Return the linearized machine coordinates of the I/O node */
return (int)lex_rank(io_node_coords, 4, dim_mach);
}
