Added twosum and inversion count

Author: cthacker-udel

pythonProblems/clrs/inversioncount.py

@@ -0,0 +1,25 @@
+def inversion_count(arr):
+    print(arr)
+    i = 0
+    j = len(arr) - 1
+    total = 0
+    while i <= j:
+        if arr[i] > arr[j]:
+            print((arr[i], arr[j]))
+            total += 1
+            j -= 1
+        else:
+            j = len(arr) - 1
+            i += 1
+    return total
+
+
+def number_of_inversions(arr):
+    if len(arr) <= 1:
+        return 0
+    return number_of_inversions(arr[:len(arr) // 2]) + number_of_inversions(arr[len(arr) // 2:]) + inversion_count(arr)
+
+
+if __name__ == '__main__':
+    glob_arr = [2, 3, 8, 6, 1]
+    print(number_of_inversions(glob_arr))

pythonProblems/clrs/twosum.py

@@ -0,0 +1,32 @@
+from typing import List
+
+
+def two_sum(a: List[int], x):
+    """
+    O(n lg n) implementation of two-sum
+
+    Args:
+        a (List[int]): _description_
+        x (_type_): _description_
+
+    Returns:
+        _type_: _description_
+    """
+    a = sorted(a)
+    i = len(a) - 1
+    j = 0
+    while i != j and j < i:
+        if a[i] + a[j] < x:
+            j += 1
+        elif a[i] + a[j] > x:
+            i -= 1
+        else:
+            print(a[i], a[j])
+            return True
+    return False
+
+
+if __name__ == '__main__':
+    arr = [1, 5, 4, 10, 2, 3]
+    _sum = 11
+    print(two_sum(arr, _sum))