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A Visual Introduction to Algorithms

Challenge: Binary Search

Implement the binary search algorithm by coding the doSearch function according to detailed pseudocode. Learn to efficiently find a target value in a sorted array or return -1 if it's not present, gaining understanding of binary search mechanics and their practical application.

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Complete the doSearch function so that it implements a binary search, following the pseudo-code below (this pseudo-code was described in the previous article):

  1. Let min = 0 and max = n - 1.

  2. If max < min, then stop: target is not present in array. Return -1.

  3. Compute guess as the average of max and min, rounded down (so that it is an integer).

  4. If array[guess] equals target, then stop. You found it! Return guess.

  5. If the guess was too low, that is, array[guess] < target, then set min = guess + 1.

  6. Otherwise, the guess was too high. Set max = guess - 1.

  7. Go back to step 2.

Java
Python
C++
JS
import java.util.Arrays;
import java.lang.Integer;
class Solution {
  // Returns either the index of the location in the array,
  // or -1 if the array did not contain the targetValue
  public static int doSearch(int[] array, int targetValue) {
      int min = 0;
      System.out.println(Arrays.toString(array));
      int max = array.length - 1;
      int guess;
      
      return -1;
  }
};