Linear Search & Binary Search
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The document discusses and compares linear and binary search algorithms. Linear search sequentially checks each element of an unsorted array to find a target value, while binary search works on a sorted array by repeatedly calculating the midpoint and comparing the target to the value there to narrow the search range. It provides steps for performing a binary search, including sorting the array, calculating the midpoint, and updating the search range based on whether the target is less than, greater than, or equal to the midpoint value.
![09/30/15 © Reem Al-Attas 4
Binary Search
2. Calculate middle = (low + high) / 2.
= (0 + 8) / 2 = 4.
If 37 == array[middle] return middle
Else if 37 < array[middle] high = middle -1
Else if 37 > array[middle] low = middle +1](https://image.slidesharecdn.com/ch12searchlinearbinary-150930234148-lva1-app6891/85/Linear-Search-Binary-Search-4-320.jpg)
![09/30/15 © Reem Al-Attas 5
Binary Search
Repeat 2. Calculate middle = (low + high) / 2.
= (0 + 3) / 2 = 1.
If 37 == array[middle] return middle
Else if 37 < array[middle] high = middle -1
Else if 37 > array[middle] low = middle +1](https://image.slidesharecdn.com/ch12searchlinearbinary-150930234148-lva1-app6891/85/Linear-Search-Binary-Search-5-320.jpg)
![09/30/15 © Reem Al-Attas 6
Binary Search
Repeat 2. Calculate middle = (low + high) / 2.
= (2 + 3) / 2 = 2.
If 37 == array[middle] return middle
Else if 37 < array[middle] high = middle -1
Else if 37 > array[middle] low = middle +1](https://image.slidesharecdn.com/ch12searchlinearbinary-150930234148-lva1-app6891/85/Linear-Search-Binary-Search-6-320.jpg)
Linear Search & Binary Search
- 2. 09/30/15 © Reem Al-Attas 2 Linear Search • Find 37? ≠ ≠ = Return 2
- 3. 09/30/15 © Reem Al-Attas 3 Binary Search • Find 37? 1. Sort Array.
- 4. 09/30/15 © Reem Al-Attas 4 Binary Search 2. Calculate middle = (low + high) / 2. = (0 + 8) / 2 = 4. If 37 == array[middle] return middle Else if 37 < array[middle] high = middle -1 Else if 37 > array[middle] low = middle +1
- 5. 09/30/15 © Reem Al-Attas 5 Binary Search Repeat 2. Calculate middle = (low + high) / 2. = (0 + 3) / 2 = 1. If 37 == array[middle] return middle Else if 37 < array[middle] high = middle -1 Else if 37 > array[middle] low = middle +1
- 6. 09/30/15 © Reem Al-Attas 6 Binary Search Repeat 2. Calculate middle = (low + high) / 2. = (2 + 3) / 2 = 2. If 37 == array[middle] return middle Else if 37 < array[middle] high = middle -1 Else if 37 > array[middle] low = middle +1
- 7. 09/30/15 © Reem Al-Attas 7 Binary Search
- 8. 09/30/15 © Reem Al-Attas 8 Binary Search • If not found stop when low > high.