1+ //The Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21
12// the algorithm has time complexity of O(n^2), very bad!
23function fibonacci ( position ) {
34 // if position is 1 or 2, the number in fibonacci sequence will be 1
4- if ( position < 3 ) {
5- return 1 ;
5+ if ( position <= 1 ) {
6+ return position ;
67 }
8+ 79 // else the element in fibonacci sequence will be the sum of
810 // element at position(p) (p -1) and (p - 2)
911 return fibonacci ( position - 2 ) + fibonacci ( position - 1 ) ;
@@ -24,8 +26,8 @@ function fibonacciMemoized(index, cache) {
2426 if ( cache [ index ] ) {
2527 return cache [ index ] ;
2628 } else {
27- if ( index < 3 ) {
28- return 1 ;
29+ if ( index <= 1 ) {
30+ return index ;
2931 } else {
3032 cache [ index ] =
3133 fibonacciMemoized ( index - 1 , cache ) +
@@ -41,7 +43,9 @@ function fibonacciMemoized(index, cache) {
4143
4244function fibonacciTabular ( n ) {
4345 const table = [ 0 , 1 ] ;
44- 46+ if ( n <= 1 ) {
47+ return n ;
48+ }
4549 for ( let i = 2 ; i <= n ; i += 1 ) {
4650 table [ i ] = table [ i - 1 ] + table [ i - 2 ] ;
4751 }
@@ -54,4 +58,4 @@ function fibonacciTabular(n) {
5458// console.log(`Fib normal - ${fibonacci(number)}`);
5559// console.log('--');
5660// console.log(`Fib memo - ${fibonacciMemoized(number)}`);
57- // console.log(`Fib table - ${fibonacciTabular(number)}`);
61+ // console.log(`Fib table - ${fibonacciTabular(number)}`);
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