Create bs_find_pair_nums.py

searching/bs_find_pair_nums.py

@@ -0,0 +1,88 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+# given a collection of numbers, find the pair 
+# of numbers that sum to a given number
+
+def bs(array, desired_num):
+
+    start = 0
+    end = len(array)
+    mid = (end - start) // 2
+
+    while len(array) > 0:
+        if array[mid] == desired_num:
+            return True
+        elif array[mid] > desired_num:
+            return bs(array[mid+1:], desired_num)
+        else:
+            return bs(array[:mid], desired_num)
+    
+    return False
+    
+
+def find_pairs_bs(array, desired_sum):
+
+    for i in range(len(array)):
+        num1 = array[i]
+        desired_num = desired_sum - num1
+        if bs(array[i + 1:], desired_num) == True:
+            return (num1, desired_num)
+
+    return False
+
+
+def find_pairs_max_sum(array, desired_sum):
+
+    i, j = 0, len(array) - 1
+
+    while i < j:
+        if array[i] + array[j] == desired_sum:
+            return array[i], array[j]
+        elif array[i] + array[j] > desired_sum:
+            j = j - 1
+        elif array[i] + array[j] < desired_sum:
+            i = i + 1
+            
+    return False
+
+def find_pairs_not_sorted(array, desired_sum):
+
+    lookup = {}
+
+    for item in array:
+        key = desired_sum - item
+
+        if key in lookup.keys():
+            lookup[key] += 1
+        else:
+            lookup[key] = 1
+
+    for item in array:
+        key = desired_sum - item
+
+        if item in lookup.keys():
+            if lookup[item] == 1: 
+                return (item, key)
+            else:
+                lookup[item] -= 1
+
+    return False
+
+
+
+if __name__ == "__main__":
+
+    desired_sum = 8
+    array1 = [1, 2, 3, 9]
+    array2 = [1, 2, 4, 5, 4]
+    array3 = [2, 1, 6, 3, 11, 2]
+
+    assert(find_pairs_bs(array1, desired_sum) == False)
+    assert(find_pairs_bs(array2, desired_sum) == (4, 4))
+    assert(find_pairs_max_sum(array1, desired_sum) == False)
+    assert(find_pairs_max_sum(array2, desired_sum) == (4,4))
+    assert(find_pairs_not_sorted(array1, desired_sum) == False)
+    assert(find_pairs_not_sorted(array2, desired_sum) == (4, 4))
+    assert(find_pairs_not_sorted(array3, desired_sum) == (2, 6))