the comparison of naive recursion and dynamic programming to compute n-th fibonacci number

fib-dp.c

#include <stdio.h>

long long fib(long long n);
long long fibs[100];

long long
main()
{
    long long i;

    for(i = 1; i <= 50; i++)
        printf("%lld ", fib(i));
}

/* fib: find the n-th fibonacci number */
long long
fib(long long n)
{
    if(fibs[n]) return fibs[n];
    if(n <= 2) {
        fibs[n] = 1;
        return fibs[n];
    };
    if(n > 2) {
        fibs[n] = fib(n-1) + fib(n-2);
        return fibs[n];
    }
}

fib.c

#include <stdio.h>

long long fib(long long n);

long long
main()
{
    long long i;

    for(i = 1; i <= 50; i++)
        printf("%lld ", fib(i));
}

/* fib: find the n-th fibonacci number */
long long
fib(long long n)
{
    if(n <= 2) return 1;
    if(n > 2) return fib(n-1) + fib(n-2);
}

result

Compile
: ~/temp $ gcc -o fib-dc fib-dc.c
: ~/temp $ gcc -o fib fib.c

Using Dynamic Programming technique
: ~/temp $ time ./fib-dp
1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181 6765 10946 17711 28657 46368 75025 121393 196418 317811 
514229 832040 1346269 2178309 3524578 5702887 9227465 14930352 24157817 39088169 63245986 102334155 165580141 26791429
6 433494437 701408733 1134903170 1836311903 2971215073 4807526976 7778742049 12586269025 
real    0m0.001s
user    0m0.000s
sys     0m0.001s

Using naive-recursion technique
: ~/temp $ time ./fib   
1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597 2584 4181 6765 10946 17711 28657 46368 75025 121393 196418 317811 
514229 832040 1346269 2178309 3524578 5702887 9227465 14930352 24157817 39088169 63245986 102334155 165580141 26791429
6 433494437 701408733 1134903170 1836311903 2971215073 4807526976 7778742049 12586269025 
real    3m21.680s
user    3m21.020s
sys     0m0.612s