wip: binarySearch

Author: TatsuyaRyujin

lesson_07/conditionals/src/lesson7.ts

@@ -43,6 +43,9 @@ export function computeFactorial(n: number): number {
  * @return An array containing the first `n` Fibonacci values.
  */
 export function getFirstNFibonacciNumbers(n: number): number[] {
+  if (n < 0) {
+    return [];
+  }
   return [];
 }
 
@@ -74,5 +77,13 @@ export function binarySearch(
   // Else if values[pivotIndex] is greater than the value, then
   // call `binarySearch(values, start, pivotIndex - 1, value)` and return its value;
   // Else call `binarySearch(values, pivotIndex + 1, end, value)` and return its value.
+
+  if (value === values[pivotIndex]) {
+    return pivotIndex;
+  } else if (value < values[pivotIndex]) {
+    binarySearch(values, start, pivotIndex - 1, value);
+  } else {
+    binarySearch(values, pivotIndex + 1, end, value);
+  }
   return -1;
 }