Package g0201_0300.s0216_combination_sum_iii

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    216 - Combination Sum III.

    Medium

    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

    • Nested Class Summary

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      Modifier and Type Class Description

    • Field Summary

      Fields 
      Modifier and Type Field Description

    • Constructor Summary

      Constructors 
      Constructor Description
      Solution()

    • Enum Constant Summary

      Enum Constants 
      Enum Constant Description