To search for a string in a file using the binary search algorithm, we first need to ensure that the file is sorted. This can be done by sorting the lines in the file alphabetically.
Once the file is sorted, we can perform the binary search algorithm to find the target string. Here are the steps to follow:
1. Set the left and right pointers to the beginning and end of the file, respectively.
2. While the left pointer is less than or equal to the right pointer:
a. Find the middle point between the left and right pointers.
b. Compare the target string with the string at the middle point in the file.
c. If the target string is less than the middle string, move the right pointer to the middle point - 1.
d. If the target string is greater than the middle string, move the left pointer to the middle point + 1.
e. If the target string is equal to the middle string, return the index of the middle string.
If the target string is not found in the file, return -1.
Here is some sample code in Python:
def binary_search_file(file_path, target_string): with open(file_path, 'r') as file: lines = file.readlines() lines.sort() left = 0 right = len(lines) - 1 while left <= right: middle = (left + right) // 2 if target_string < lines[middle]: right = middle - 1 elif target_string > lines[middle]: left = middle + 1 else: return middle return -1
This code takes the file path and target string as input and returns the index of the target string in the file, or -1 if it is not found.
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