90 lines
2.0 KiB
C
90 lines
2.0 KiB
C
#include <malloc.h>
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#include "pythagorean_triplet.h"
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#define POOL_SIZE 10
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/* V1: initial version
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* V2: cormetic changes
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* V3: add pool for realloc instead of single realloc
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*/
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void free_triplets(triplets_t *t)
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{
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free(t->triplets);
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free(t);
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}
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static triplets_t *new_triplet()
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{
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triplets_t *t=malloc(sizeof(triplets_t));
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if (t) {
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t->count = 0;
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t->pool = 0;
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t->triplets = NULL;
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}
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return t;
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}
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static triplets_t *add_triplet(triplets_t *t, const uint16_t a, const uint16_t b,
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const uint16_t c)
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{
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/* we may directly call add_triplet() without new_triplet. Not used here,
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* but could be useful if triplets_with_sum() would return NULL when no
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* solution found.
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*/
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if (! (t || (t = new_triplet())))
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return NULL;
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if (t->count == t->pool) {
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t->pool += POOL_SIZE;
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if (!(t->triplets = realloc(t->triplets, sizeof(triplets_t) +
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t->pool * sizeof(triplet_t)))) {
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free(t);
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return NULL;
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}
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}
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t->triplets[t->count] = (triplet_t) {a, b, c};
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t->count++;
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return t;
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}
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/* algorithm from : https://stackoverflow.com/a/2818750/3079831
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*/
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triplets_t *triplets_with_sum(uint16_t sum)
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{
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int a, b, c;
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triplets_t *t;
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if (!(t = new_triplet()))
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return NULL;
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if (sum%2)
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return t;
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for (a = 1; a <= sum/3; a++) {
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for (b = a + 1; b <= sum/2; b++) {
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c = sum - a - b;
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if (a*a + b*b == c*c)
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if (!(t = add_triplet(t, a, b, c)))
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return NULL;
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}
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}
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return t;
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}
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/* See GNUmakefile below for explanation
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* https://github.com/braoult/exercism/blob/master/c/templates/GNUmakefile
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*/
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#ifdef UNIT_TEST
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int main(int ac, char **av)
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{
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int arg=1;
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resistor_band_t i[2];
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for (; arg<ac-1; ++arg, ++arg) {
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*i=atoi(av[arg]);
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*(i+1)=atoi(av[arg+1]);
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printf("color(%d, %d)=%d\n", i[0], i[1], color_code(i));
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}
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}
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#endif
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