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/*
Projet d'algorithmique et programmation 2013-2014
(cours de C.Matthieu et J.Stern)
Alex AUVOLAT, Mendes OULAMARA
Implémentation des ensembles d'entiers sous forme de bitsets.
Code sous la juridiction de Mendes OULAMARA.
*/
#include "sets.h"
#include <stdlib.h>
#include <stdio.h>
#include <assert.h>
#define SCOD (unsigned long long)(8*sizeof(unsigned long long))
int nbCells(int n){ //the mathematical ceil function
if(n == (n/SCOD)*SCOD)
return n/SCOD;
else
return n/SCOD+1;
}
int nb_one(unsigned long long x) { //the hamming weight of x
assert(SCOD==64);
//1
x = (x & 0x5555555555555555) + ((x >> 1) & 0x5555555555555555); // mask : 0101010101...
//2
x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333); // mask : 001100110011...
//4
x = (x & 0x0F0F0F0F0F0F0F0F) + ((x >> 4) & 0x0F0F0F0F0F0F0F0F); // mask : 000011110000....
//8
x = (x & 0x00FF00FF00FF00FF) + ((x >> 8) & 0x00FF00FF00FF00FF); // etc.
//16
x = (x & 0x0000FFFF0000FFFF) + ((x >> 16) & 0x0000FFFF0000FFFF);
//32
x = (x & 0x00000000FFFFFFFF) + ((x >> 32) & 0x00000000FFFFFFFF);
return x;
}
int set_size(const set s){
return s->size;
}
set empty_set(int n){
assert(n > 0);
int i;
int NC = nbCells(n);
char *p = malloc(sizeof(struct bitset_descriptor) + (SCOD * NC) / 8);
set res = (struct bitset_descriptor*)p;
res->tab = (unsigned long long*)((char*)(p + sizeof(struct bitset_descriptor)));
res->N = n;
res->size = 0;
for(i = 0; i < NC; i++)
res->tab[i] = (unsigned long long) (0);
return res;
}
set copy_set(const set s){
set res = empty_set(s->N);
res->size = s->size;
int NC = nbCells(s->N), i;
for(i = 0; i < NC; i++)
res->tab[i] = s->tab[i];
return res;
}
void delete_set(set a){
free(a);
}
void set_union_ip(set a, const set b){
if(a->N != b->N){
printf("Union failed : the sets don't have the same size\n");
assert(a->N == b->N);
}
int NC = nbCells(a->N), i;
a->size=0;
for(i = 0; i < NC; i++) {
a->tab[i] = a->tab[i]|b->tab[i];
a->size += nb_one(a->tab[i]);
}
}
void set_inter_ip(set a, const set b){
if(a->N != b->N){
printf("Intersection failed : the sets don't have the same size\n");
assert(a->N == b->N);
}
int NC = nbCells(a->N), i;
a->size=0;
for(i = 0; i < NC; i++){
a->tab[i] = a->tab[i]&b->tab[i];
a->size += nb_one(a->tab[i]);
}
assert((a->N%SCOD == 0) || (a->tab[NC-1]>>(a->N%SCOD)) == 0);
}
void set_diff_ip(set a, const set b){
if(a->N != b->N){
printf("Difference failed : the sets don't have the same size\n");
assert(a->N == b->N);
}
int NC = nbCells(a->N), i;
a->size = 0;
for(i = 0; i < NC; i++) {
a->tab[i] = a->tab[i] & (~b->tab[i]);
a->size += nb_one(a->tab[i]);
}
assert((a->N%SCOD == 0) || (a->tab[NC-1]>>(a->N%SCOD)) == 0);
}
bool is_set_empty(const set s){
return (s->size == 0);
}
bool sets_equal(const set a, const set b){
if(a->N != b->N)
return false;
int i, NC = nbCells(a->N);
for(i = 0; i < NC; i++){
if(a->tab[i] != b->tab[i])
return false;
}
assert(a->size == b->size);
return true;
}
inline bool set_mem(int x, const set s){
unsigned long long ux = x;
if (!(x < s->N && x >= 0)) {
printf("Invalid argument for set_mem : %d\n", x);
assert(x < s->N && x >= 0);
}
return (s->tab[ux/SCOD]>>(ux%SCOD))&1;
}
int dyadic_val(unsigned long long x){
if(x == 0) {
printf("Infinite valuation\n");
assert(false);
}
int i = 0;
while (((x>>i)&1) == 0) i++;
return i;
}
int elt_of_set(const set s){
int N=nbCells(s->N), i;
for(i=0; i<N; i++)
if(s->tab[i] != 0)
return i*SCOD + dyadic_val(s->tab[i]);
printf("No element in an empty set!\n");
dump_set(s);
assert(false);
}
int elt_of_set_heur(const set s, int h){
int N=nbCells(s->N), i, cell;
if(s->tab[h/SCOD]>>(h%SCOD) !=0)
return h + dyadic_val(s->tab[h/SCOD]>>(h%SCOD)) ;
for(i=0; i<N; i++) {
cell = (i + h/SCOD + 1) % N;
if(s->tab[cell] != 0)
return cell*SCOD + dyadic_val(s->tab[cell]);
}
printf("No element in an empty set!\n");
dump_set(s);
assert(false);
}
void set_add_ip(int x, set s){
assert(x < s->N);
unsigned long long ux = x;
if(! set_mem(ux, s)){
s->tab[ux/SCOD] = s->tab[ux/SCOD] | (unsigned long long)(1)<<(ux%SCOD);
s->size = s->size+1;
}
}
void set_remove_ip(int x, set s){
unsigned long long ux = x;
if(set_mem(ux, s) ) {
s->tab[ux/SCOD] = s->tab[ux/SCOD] & (~((unsigned long long)(1)<<(ux%SCOD)));
s->size = s->size-1;
}
}
void dump_set(const set s){
int i=0;
printf("[");
for(i=0; i < s->N; i++)
if(set_mem(i, s))
printf(" %d ", i);
printf("] (%d)\n", s->size);
}
set full_set(int n) {
set r = empty_set(n);
r->size = n;
int NC=nbCells(n), i;
for(i=0; i< NC; i++)
r->tab[i]=0xFFFFFFFFFFFFFFFF;
r->tab[NC-1] = ( r->tab[NC-1]>>( (SCOD-(n%SCOD))%SCOD ) );
assert((n%SCOD == 0) || (r->tab[NC-1]>>(n%SCOD)) == 0);
return r;
}
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