Package g0201_0300.s0216_combination_sum_iii

Class Solution

java.lang.Object

g0201_0300.s0216_combination_sum_iii.Solution

public class Solution
extends Object

216 - Combination Sum III.<p>Medium</p> <p>Find all valid combinations of <code>k</code> numbers that sum up to <code>n</code> such that the following conditions are true:</p> <ul> <li>Only numbers <code>1</code> through <code>9</code> are used.</li> <li>Each number is used <strong>at most once</strong>.</li> </ul> <p>Return <em>a list of all possible valid combinations</em>. The list must not contain the same combination twice, and the combinations may be returned in any order.</p> <p><strong>Example 1:</strong></p> <p><strong>Input:</strong> k = 3, n = 7</p> <p><strong>Output:</strong> <a href="1,2,4">1,2,4</a></p> <p><strong>Explanation:</strong></p> <pre><code> 1 + 2 + 4 = 7 There are no other valid combinations. </code></pre> <p><strong>Example 2:</strong></p> <p><strong>Input:</strong> k = 3, n = 9</p> <p><strong>Output:</strong> [[1,2,6],[1,3,5],[2,3,4]]</p> <p><strong>Explanation:</strong></p> <pre><code> 1 + 2 + 6 = 9 1 + 3 + 5 = 9 2 + 3 + 4 = 9 There are no other valid combinations. </code></pre> <p><strong>Example 3:</strong></p> <p><strong>Input:</strong> k = 4, n = 1</p> <p><strong>Output:</strong> []</p> <p><strong>Explanation:</strong></p> <pre><code> 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. </code></pre> <p><strong>Example 4:</strong></p> <p><strong>Input:</strong> k = 3, n = 2</p> <p><strong>Output:</strong> []</p> <p><strong>Explanation:</strong> There are no valid combinations.</p> <p><strong>Example 5:</strong></p> <p><strong>Input:</strong> k = 9, n = 45</p> <p><strong>Output:</strong> <a href="1,2,3,4,5,6,7,8,9">1,2,3,4,5,6,7,8,9</a></p> <p><strong>Explanation:</strong></p> <pre><code> 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 = 45 There are no other valid combinations. </code></pre> <p><strong>Constraints:</strong></p> <ul> <li><code>2 <= k <= 9</code></li> <li><code>1 <= n <= 60</code></li> </ul>

Constructor Summary

Constructors

Constructor	Description
Solution()

Method Summary

Modifier and Type	Method	Description
List<List<Integer>>	combinationSum3(int k, int n)

Methods inherited from class java.lang.Object

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

Constructor Details

Solution

public Solution()

Method Details

combinationSum3

public List<List<Integer>> combinationSum3(int k,
 int n)