created problem58

Author: dampdigits

problem58/README.md

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+# 216. 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.
+
+## Example 2:
+
+Input: k = 3, n = 9
+Output: [[1,2,6],[1,3,5],[2,3,4]]
+Explanation:
+1 + 2 + 6 = 9
+1 + 3 + 5 = 9
+2 + 3 + 4 = 9
+There are no other valid combinations.
+
+## Example 3:
+
+Input: k = 4, n = 1
+Output: []
+Explanation: There are no valid combinations.
+Using 4 different numbers in the range [1,9], the smallest sum we can get is 1+2+3+4 = 10 and since 10 > 1, there are no valid combination.
+ 
+
+## Constraints:
+
+2 <= k <= 9
+1 <= n <= 60