move-files-and-2-renames (#4285)

maths/triplet_sum.py

@@ -0,0 +1,89 @@
+"""
+Given an array of integers and another integer target,
+we are required to find a triplet from the array such that it's sum is equal to
+the target.
+"""
+from __future__ import annotations
+
+from itertools import permutations
+from random import randint
+from timeit import repeat
+
+
+def make_dataset() -> tuple[list[int], int]:
+    arr = [randint(-1000, 1000) for i in range(10)]
+    r = randint(-5000, 5000)
+    return (arr, r)
+
+
+dataset = make_dataset()
+
+
+def triplet_sum1(arr: list[int], target: int) -> tuple[int, int, int]:
+    """
+    Returns a triplet in the array with sum equal to target,
+    else (0, 0, 0).
+    >>> triplet_sum1([13, 29, 7, 23, 5], 35)
+    (5, 7, 23)
+    >>> triplet_sum1([37, 9, 19, 50, 44], 65)
+    (9, 19, 37)
+    >>> arr = [6, 47, 27, 1, 15]
+    >>> target = 11
+    >>> triplet_sum1(arr, target)
+    (0, 0, 0)
+    """
+    for triplet in permutations(arr, 3):
+        if sum(triplet) == target:
+            return tuple(sorted(triplet))
+    return (0, 0, 0)
+
+
+def triplet_sum2(arr: list[int], target: int) -> tuple[int, int, int]:
+    """
+    Returns a triplet in the array with sum equal to target,
+    else (0, 0, 0).
+    >>> triplet_sum2([13, 29, 7, 23, 5], 35)
+    (5, 7, 23)
+    >>> triplet_sum2([37, 9, 19, 50, 44], 65)
+    (9, 19, 37)
+    >>> arr = [6, 47, 27, 1, 15]
+    >>> target = 11
+    >>> triplet_sum2(arr, target)
+    (0, 0, 0)
+    """
+    arr.sort()
+    n = len(arr)
+    for i in range(n - 1):
+        left, right = i + 1, n - 1
+        while left < right:
+            if arr[i] + arr[left] + arr[right] == target:
+                return (arr[i], arr[left], arr[right])
+            elif arr[i] + arr[left] + arr[right] < target:
+                left += 1
+            elif arr[i] + arr[left] + arr[right] > target:
+                right -= 1
+    return (0, 0, 0)
+
+
+def solution_times() -> tuple[float, float]:
+    setup_code = """
+from __main__ import dataset, triplet_sum1, triplet_sum2
+"""
+    test_code1 = """
+triplet_sum1(*dataset)
+"""
+    test_code2 = """
+triplet_sum2(*dataset)
+"""
+    times1 = repeat(setup=setup_code, stmt=test_code1, repeat=5, number=10000)
+    times2 = repeat(setup=setup_code, stmt=test_code2, repeat=5, number=10000)
+    return (min(times1), min(times2))
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()
+    times = solution_times()
+    print(f"The time for naive implementation is {times[0]}.")
+    print(f"The time for optimized implementation is {times[1]}.")