I was recently asked to generate Fibonacci numbers based on a given index in an interview and wasn't able to come up with the answer off the cuff.
Using Recursion
public int fib( int n )
{
if ( n < 2 ) return n;
return fib( n - 1 ) + fib( n - 2 );
}
Using Iteration
public int fib( int n )
{
int prev1 = 0;
int prev2 = 1;
int savePrev1;
for( int i = 0; i < n; i++ )
{
savePrev1 = prev1;
prev1 = prev2;
prev2 = savePrev1 + prev2;
}
return prev1;
}
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