Algorithms : complete 01-algorithmic_toolbox 01-intro

1 files changed, 18 insertions, 1 deletions

diff --git a/01-algorithmic_toolbox/01-intro/01-fibonacci/fibonacci.cpp b/01-algorithmic_toolbox/01-intro/01-fibonacci/fibonacci.cpp
index adc7404..c2564b8 100644
--- a/01-algorithmic_toolbox/01-intro/01-fibonacci/fibonacci.cpp
+++ b/01-algorithmic_toolbox/01-intro/01-fibonacci/fibonacci.cpp
@@ -7,10 +7,27 @@ int calc_fib(int n) {
     return calc_fib(n - 1) + calc_fib(n - 2);
 }
 
+int fib(int n)
+{
+    int a, b, c, i;
+
+    if (n <= 1)
+        return n;
+
+    a = 0; b = 1;
+    for(i = 1; i < n; i++) {
+        c = a + b;
+        a = b;
+        b = c;
+    }
+
+    return b;
+}
+
 int main() {
     int n = 0;
     std::cin >> n;
 
-    std::cout << calc_fib(n) << '\n';
+    std::cout << fib(n) << '\n';
     return 0;
 }