Data commit

Task/Fibonacci-sequence/C/fibonacci-sequence-1.c

@@ -0,0 +1,3 @@
+long long fibb(long long a, long long b, int n) {
+    return (--n>0)?(fibb(b, a+b, n)):(a);
+}

Task/Fibonacci-sequence/C/fibonacci-sequence-2.c

@@ -0,0 +1,9 @@
+long long int fibb(int n) {
+	int fnow = 0, fnext = 1, tempf;
+	while(--n>0){
+		tempf = fnow + fnext;
+		fnow = fnext;
+		fnext = tempf;
+		}
+		return fnext;	
+}

Task/Fibonacci-sequence/C/fibonacci-sequence-3.c

@@ -0,0 +1,6 @@
+#include <tgmath.h>
+#define PHI ((1 + sqrt(5))/2)
+
+long long unsigned fib(unsigned n) {
+    return floor( (pow(PHI, n) - pow(1 - PHI, n))/sqrt(5) );
+}

Task/Fibonacci-sequence/C/fibonacci-sequence-4.c

@@ -0,0 +1,37 @@
+#include <stdio.h>
+typedef enum{false=0, true=!0} bool;
+typedef void iterator;
+
+#include <setjmp.h>
+/* declare label otherwise it is not visible in sub-scope */
+#define LABEL(label) jmp_buf label; if(setjmp(label))goto label;
+#define GOTO(label) longjmp(label, true)
+
+/* the following line is the only time I have ever required "auto" */
+#define FOR(i, iterator) { auto bool lambda(i); yield_init = (void *)&lambda; iterator; bool lambda(i)
+#define DO {
+#define     YIELD(x) if(!yield(x))return
+#define     BREAK    return false
+#define     CONTINUE return true
+#define OD CONTINUE; } }
+
+static volatile void *yield_init; /* not thread safe */
+#define YIELDS(type) bool (*yield)(type) = yield_init
+
+iterator fibonacci(int stop){
+    YIELDS(int);
+    int f[] = {0, 1};
+    int i;
+    for(i=0; i<stop; i++){
+        YIELD(f[i%2]);
+        f[i%2]=f[0]+f[1];
+    }
+}
+
+main(){
+  printf("fibonacci: ");
+  FOR(int i, fibonacci(16)) DO
+    printf("%d, ",i);
+  OD;
+  printf("...\n");
+}

Task/Fibonacci-sequence/C/fibonacci-sequence-5.c

@@ -0,0 +1,74 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <gmp.h>
+
+typedef struct node node;
+struct node {
+	int n;
+	mpz_t v;
+	node *next;
+};
+
+#define CSIZE 37
+node *cache[CSIZE];
+
+// very primitive linked hash table
+node * find_cache(int n)
+{
+	int idx = n % CSIZE;
+	node *p;
+
+	for (p = cache[idx]; p && p->n != n; p = p->next);
+	if (p) return p;
+
+	p = malloc(sizeof(node));
+	p->next = cache[idx];
+	cache[idx] = p;
+
+	if (n < 2) {
+		p->n = n;
+		mpz_init_set_ui(p->v, 1);
+	} else {
+		p->n = -1; // -1: value not computed yet
+		mpz_init(p->v);
+	}
+	return p;
+}
+
+mpz_t tmp1, tmp2;
+mpz_t *fib(int n)
+{
+	int x;
+	node *p = find_cache(n);
+
+	if (p->n < 0) {
+		p->n = n;
+		x = n / 2;
+
+		mpz_mul(tmp1, *fib(x-1), *fib(n - x - 1));
+		mpz_mul(tmp2, *fib(x), *fib(n - x));
+		mpz_add(p->v, tmp1, tmp2);
+	}
+	return &p->v;
+}
+
+int main(int argc, char **argv)
+{
+	int i, n;
+	if (argc < 2) return 1;
+
+	mpz_init(tmp1);
+	mpz_init(tmp2);
+
+	for (i = 1; i < argc; i++) {
+		n = atoi(argv[i]);
+		if (n < 0) {
+			printf("bad input: %s\n", argv[i]);
+			continue;
+		}
+
+		// about 75% of time is spent in printing
+		gmp_printf("%Zd\n", *fib(n));
+	}
+	return 0;
+}