diff --git a/matrix/binary_search_matrix.py b/matrix/binary_search_matrix.py new file mode 100644 index 000000000000..6f203b7a3484 --- /dev/null +++ b/matrix/binary_search_matrix.py @@ -0,0 +1,57 @@ +def binary_search(array: list, lower_bound: int, upper_bound: int, value: int) -> int: + """ + This function carries out Binary search on a 1d array and + return -1 if it do not exist + array: A 1d sorted array + value : the value meant to be searched + >>> matrix = [1, 4, 7, 11, 15] + >>> binary_search(matrix, 0, len(matrix) - 1, 1) + 0 + >>> binary_search(matrix, 0, len(matrix) - 1, 23) + -1 + """ + + r = int((lower_bound + upper_bound) // 2) + if array[r] == value: + return r + if lower_bound >= upper_bound: + return -1 + if array[r] < value: + return binary_search(array, r + 1, upper_bound, value) + else: + return binary_search(array, lower_bound, r - 1, value) + + +def mat_bin_search(value: int, matrix: list) -> list: + """ + This function loops over a 2d matrix and calls binarySearch on + the selected 1d array and returns [-1, -1] is it do not exist + value : value meant to be searched + matrix = a sorted 2d matrix + >>> matrix = [[1, 4, 7, 11, 15], + ... [2, 5, 8, 12, 19], + ... [3, 6, 9, 16, 22], + ... [10, 13, 14, 17, 24], + ... [18, 21, 23, 26, 30]] + >>> target = 1 + >>> mat_bin_search(target, matrix) + [0, 0] + >>> target = 34 + >>> mat_bin_search(target, matrix) + [-1, -1] + """ + index = 0 + if matrix[index][0] == value: + return [index, 0] + while index < len(matrix) and matrix[index][0] < value: + r = binary_search(matrix[index], 0, len(matrix[index]) - 1, value) + if r != -1: + return [index, r] + index += 1 + return [-1, -1] + + +if __name__ == "__main__": + import doctest + + doctest.testmod()