feat(day 7): add two-sum target solver with brute force and hash map approches

Author: JohnSunny21

FreeCodeCamp/CodingQ/targetedSum.py

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+"""
+================================================>       Targeted Sum        <====================================================================================
+Given an array of numbers and an integer target, find two unique numbers in the array that add up to the target value. Return an array with the indices of those two numbers, or "Target not found" if no two numbers sum up to the target.
+
+The returned array should have the indices in ascending order.
+
+
+=======================================================================================================================================
+O/P : ====>
+
+1. find_target([2, 7, 11, 15], 9) should return [0, 1].
+2. find_target([3, 2, 4, 5], 6) should return [1, 2].
+3. find_target([1, 3, 5, 6, 7, 8], 15) should return [4, 5].
+4. find_target([1, 3, 5, 7], 14) should return 'Target not found'.
+"""
+
+# Brute force 
+# Time complexity : O(n**2)
+# Space Complexity : O(1)
+def find_target_brute(arr,target):
+
+    n = len(arr)
+    for i in range(n):
+        for j in range(i+1, n):
+            if arr[i] + arr[j] == target:
+                return [i,j]
+    else:
+        return "Target not found"
+    
+def find_target(arr,target):
+    c = {}
+    for i in range(len(arr)):
+        c[arr[i]] = i
+
+    for i in range(len(arr)):
+        y = target - arr[i]
+
+        if y in c and c[y] != i:
+            return [i,c[y]]
+    else:
+        return "Target not found"
+    
+
+if __name__ == "__main__":
+    print(find_target([2,7,11,15],9))
+

FreeCodeCamp/CodingQ/targetedSumTest.py

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+import unittest
+from targetedSum import find_target
+
+class targetedSumTest(unittest.TestCase):
+
+    def test1(self):
+        self.assertEqual(find_target([2,7,11,15],9),[0,1])
+
+    def test2(self):
+        self.assertEqual(find_target([3,2,4,5],6),[1,2])
+
+    def test3(self):
+        self.assertEqual(find_target([1,3,5,6,7,8],15),[4,5])
+
+    def test4(self):
+        self.assertEqual(find_target([1,3,5,7],14),"Target not found")
+
+
+
+if __name__ == "__main__":
+    unittest.main()