Recursion for Coding Interviews in Python/

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Solution Review: Search First Occurrence of a Number

Solution Review: Search First Occurrence of a Number

This review provides a detailed analysis for finding the first occurrence of a given number in an array.

We'll cover the following...

Solution #1: Iterative Method

Python 3.5
def firstIndex(arr, testVariable, currentIndex): # returns the first occurrence of testVariable
  while currentIndex < len(arr) : # Iterate over the array
    if arr[currentIndex] == testVariable :  # Return the current index if testVariable found
      return currentIndex
      
    currentIndex += 1
  return -1
# Driver Code
arr = [9, 8, 1, 8, 1, 7]
testVariable = 1
currentIndex = 0
print(firstIndex(arr, testVariable, currentIndex))

Explanation

To find the first occurrence of testVariable we iterate over the entire array and return the currentIndex when testVariable is found. Let’s look at an illustration:

Solution #2: Recursive Method

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