fix: use bigint type

Author: JCPedroza

src/algorithms/math/fibonacci/fibonacci-sequence-floop.js

@@ -3,7 +3,7 @@
  * Time complexity: O(n)
  * Space complexity: O(n)
  * @param {number} length Length of the Fibonacci sequence.
- * @returns {number[]} Fibonacci sequence of the specified length.
+ * @returns {bigint[]} Fibonacci sequence of the specified length.
  */
 const fibonacciSequence = (length) => {
   if (length === 0) return []
@@ -12,7 +12,9 @@ const fibonacciSequence = (length) => {
   const sequence = [0n, 1n]
 
   for (let index = 2; index < length; index++) {
-    sequence.push(sequence.at(-1) + sequence.at(-2))
+    const idxMinOne = sequence.at(-1) ?? 0n
+    const idxMinTwo = sequence.at(-2) ?? 0n
+    sequence.push(idxMinOne + idxMinTwo)
   }
 
   return sequence

src/algorithms/math/fibonacci/fibonacci-sequence-reduce.js

@@ -3,14 +3,16 @@
  * Time complexity: O(n)
  * Space complexity: O(n)
  * @param {number} length Length of the Fibonacci sequence.
- * @returns {number[]} Fibonacci sequence of the specified length.
+ * @returns {bigint[]} Fibonacci sequence of the specified length.
  */
 const fibonacciSequence = (length) => {
   const fibos = [0n, 1n]
   if (length < 2) return fibos.slice(0, length)
 
   return [...Array(length - 2).keys()].reduce(fibos => {
-    fibos.push(fibos.at(-1) + fibos.at(-2))
+    const idxMinOne = fibos.at(-1) ?? 0n
+    const idxMinTwo = fibos.at(-2) ?? 0n
+    fibos.push(idxMinOne + idxMinTwo)
     return fibos
   }, fibos)
 }

src/algorithms/math/fibonacci/fibonacci-sequence-rmemo.js

@@ -3,14 +3,15 @@
  * Time complexity: O(n)
  * Space complexity: O(n)
  * @param {number} length Length of the Fibonacci sequence.
- * @returns {number[]} Fibonacci sequence of the specified length.
+ * @returns {bigint[]} Fibonacci sequence of the specified length.
  */
 const fibonacciSequence = (length) => {
   if (length === 0) return []
   if (length === 1) return [0n]
 
   const sequence = [0n, 1n]
 
+  /** @param {number} n */
   const fibo = (n) => {
     if (typeof sequence[n] !== 'undefined') return sequence[n]
     sequence[n] = fibo(n - 1) + fibo(n - 2)