Merge pull request #94 from williamvietnguyen/fibberoni

Fibberoni

1 files changed, 39 insertions, 0 deletions

diff --git a/entries/williamvietnguyen/fibberoni.c b/entries/williamvietnguyen/fibberoni.c
new file mode 100644
index 0000000..e3c3c4d
--- /dev/null
+++ b/entries/williamvietnguyen/fibberoni.c
@@ -0,0 +1,39 @@
+/* fib.c */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int fibberoni_compute(int n, int* cache) {
+    if (n < 2) {
+        return n;
+    }
+    if (cache[n] != -1) {
+        return cache[n];
+    }
+    cache[n] = fibberoni_compute(n - 1, cache) + fibberoni_compute(n - 2, cache);
+    return cache[n];
+}
+
+int fibberoni(int n) {
+    int sign, result, cache[abs(n) + 1];
+    sign = (n < 0) ? -1 : 1;
+    memset(cache, -1, sizeof(int) * (abs(n) + 1));
+    result = fibberoni_compute(abs(n), cache);
+    return sign * result;
+}
+
+void usage() {
+   printf("Usage: ./fibberoni -12\n");
+   exit(EXIT_FAILURE);
+}
+
+int main(int argc, char** argv) {
+    int n, result;
+    if (argc < 2) {
+        usage();
+    }
+    n = atoi(argv[1]);
+    result = fibberoni(n);
+    printf("%d", result);
+    exit(EXIT_SUCCESS);
+}