Combination Sum III

Author: Shikha-code36

Backtracking/216-Combination-Sum-III.py

@@ -0,0 +1,34 @@
+'''Leetcode- https://leetcode.com/problems/combination-sum-iii/'''
+'''
+Find all valid combinations of k numbers that sum up to n such that the following conditions are true:
+
+Only numbers 1 through 9 are used.
+Each number is used at most once.
+Return a list of all possible valid combinations. The list must not contain the same combination twice, and the combinations may be returned in any order.
+
+ 
+
+Example 1:
+
+Input: k = 3, n = 7
+Output: [[1,2,4]]
+Explanation:
+1 + 2 + 4 = 7
+There are no other valid combinations.
+'''
+
+
+def combinationSum3(k, n):
+    res = []
+
+    def backtrack(cur, n, start):
+        if k == len(cur):
+            if n == 0:
+                res.append(cur.copy())
+            return
+        for i in range(start, 10):
+            cur.append(i)
+            backtrack(cur, n-i, i+1)
+            cur.pop()
+    backtrack([], n, 1)
+    return res

README.md

@@ -15,5 +15,6 @@ Check the notes for the explaination - [Notes](https://stingy-shallot-4ea.notion
     - [x] [Combinations](Backtracking/77-Combinations.py)
     - [x] [Combination Sum](Backtracking/39-Combination-Sum.py)
     - [x] [Combination Sum II](Backtracking/40-Combination-Sum-II.py)
+    - [x] [Combination Sum III](Backtracking/216-Combination-Sum-III.py)