Package g0001_0100.s0077_combinations

Class Solution

  • All Implemented Interfaces:
    
public final class Solution

    77 - Combinations.

    Medium

    Given two integers n and k, return all possible combinations of k numbers chosen from the range [1, n].

    You may return the answer in any order.

    Example 1:

    Input: n = 4, k = 2

    Output: [1,2,1,3,1,4,2,3,2,4,3,4]

    Explanation: There are 4 choose 2 = 6 total combinations. Note that combinations are unordered, i.e., 1,2 and 2,1 are considered to be the same combination.

    Example 2:

    Input: n = 1, k = 1

    Output: [1]

    Explanation: There is 1 choose 1 = 1 total combination.

    Constraints:

    • 1 <= n <= 20

    • 1 <= k <= n

    • Nested Class Summary

      Nested Classes 
      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

    • Method Summary

      Modifier and Type Method Description
      final List<List<Integer>> combine(Integer n, Integer k)

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait