Added a function to check ordering in ODA and DODA

pydatastructs/linear_data_structures/__init__.py

@@ -32,6 +32,7 @@
     bucket_sort,
     cocktail_shaker_sort,
     quick_sort,
-    longest_common_subsequence
+    longest_common_subsequence,
+    is_ordered
 )
 __all__.extend(algorithms.__all__)

pydatastructs/linear_data_structures/algorithms.py

@@ -14,7 +14,8 @@
     'bucket_sort',
     'cocktail_shaker_sort',
     'quick_sort',
-    'longest_common_subsequence'
+    'longest_common_subsequence',
+    'is_ordered'
 ]
 
 def _merge(array, sl, el, sr, er, end, comp):
@@ -787,3 +788,38 @@ def longest_common_subsequence(seq1: OneDimensionalArray, seq2: OneDimensionalAr
                     check_mat[i][j] = check_mat[i][j-1]
 
     return OneDimensionalArray(seq1._dtype, check_mat[row][col][-1])
+
+def is_ordered(array, start, end, comp):
+    """
+    Checks whether the given array is sorted or not.
+
+    Parameters
+    =========
+    array : OneDimensionalArray
+        The array which is to be checked for sort.
+
+    start : int
+        The starting index of the portion of array to be checked.
+
+    end : int
+        The ending index of the portion of array to be checked.
+
+    Examples
+    ========
+
+    >>> from pydatastructs import OneDimensionalArray, is_ordered
+    >>> arr = OneDimensionalArray(int, [4, 3, 2, 1])
+    >>> is_ordered(arr, 0, 3, None)
+    False
+    >>> arr1 = OneDimensionalArray(int, [1, 2, 3])
+    >>> is_ordered(arr1, 0, 2, None)
+    True
+
+    """
+    if comp is None:
+        comp = lambda a, b: a < b
+
+    for i in range(start + 1, end + 1):
+        if(comp(array[i], array[i - 1])):
+            return False
+    return True

pydatastructs/linear_data_structures/tests/test_algorithms.py

@@ -1,7 +1,7 @@
 from pydatastructs import (
     merge_sort_parallel, DynamicOneDimensionalArray,
     OneDimensionalArray, brick_sort, brick_sort_parallel,
-    heapsort, matrix_multiply_parallel, counting_sort, bucket_sort, cocktail_shaker_sort, quick_sort, longest_common_subsequence)
+    heapsort, matrix_multiply_parallel, counting_sort, bucket_sort, cocktail_shaker_sort, quick_sort, longest_common_subsequence, is_sorted)
 
 
 from pydatastructs.utils.raises_util import raises
@@ -126,3 +126,36 @@ def test_longest_common_sequence():
     Z = ODA(int, [])
     output = longest_common_subsequence(Y, Z)
     assert str(output) == '[]'
+
+def test_is_sorted():
+    ODA = OneDimensionalArray
+
+    expected_result = True
+
+    arr = ODA(int,[1,2,5,6])
+    output = is_sorted(arr,0,len(arr)-1)
+    assert output == expected_result
+
+    expected_result = False
+
+    arr1 = ODA(int,[4,3,2,1])
+    output = is_sorted(arr1,0,len(arr1)-1)
+    assert output == expected_result
+
+    expected_result = True
+
+    arr2 = ODA(int,[6,1,2,3,4,5])
+    output = is_sorted(arr2,1,5)
+    assert output == expected_result
+
+    expected_result = False
+
+    arr3 = ODA(int,[0,-1,-2,-3,-4,4])
+    output = is_sorted(arr3,0,5)
+    assert output == expected_result
+
+    expected_result = True
+
+    arr4 = ODA(int,[1,2,3,4,5,6,7,8,9,10])
+    output = is_sorted(arr4,0,9)
+    assert output == expected_result