Project Notes

Combination Sum III

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Description

tab: English
 
<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>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
 
<pre>
<strong>Input:</strong> k = 3, n = 7
<strong>Output:</strong> [[1,2,4]]
<strong>Explanation:</strong>
1 + 2 + 4 = 7
There are no other valid combinations.</pre>
 
<p><strong class="example">Example 2:</strong></p>
 
<pre>
<strong>Input:</strong> k = 3, n = 9
<strong>Output:</strong> [[1,2,6],[1,3,5],[2,3,4]]
<strong>Explanation:</strong>
1 + 2 + 6 = 9
1 + 3 + 5 = 9
2 + 3 + 4 = 9
There are no other valid combinations.
</pre>
 
<p><strong class="example">Example 3:</strong></p>
 
<pre>
<strong>Input:</strong> k = 4, n = 1
<strong>Output:</strong> []
<strong>Explanation:</strong> 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 &gt; 1, there are no valid combination.
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li><code>2 &lt;= k &lt;= 9</code></li>
	<li><code>1 &lt;= n &lt;= 60</code></li>
</ul>
 
 
 
---
 
[submissions](https://leetcode.com/problems/combination-sum-iii/submissions/) | [solutions](https://leetcode.com/problems/combination-sum-iii/solutions/)
 
 
tab: 中文
 
<p>找出所有相加之和为&nbsp;<code>n</code><em> </em>的&nbsp;<code>k</code><strong>&nbsp;</strong>个数的组合，且满足下列条件：</p>
 
<ul>
	<li>只使用数字1到9</li>
	<li>每个数字&nbsp;<strong>最多使用一次</strong>&nbsp;</li>
</ul>
 
<p>返回 <em>所有可能的有效组合的列表</em> 。该列表不能包含相同的组合两次，组合可以以任何顺序返回。</p>
 
<p>&nbsp;</p>
 
<p><strong>示例 1:</strong></p>
 
<pre>
<strong>输入:</strong> <em><strong>k</strong></em> = 3, <em><strong>n</strong></em> = 7
<strong>输出:</strong> [[1,2,4]]
<strong>解释:</strong>
1 + 2 + 4 = 7
没有其他符合的组合了。</pre>
 
<p><strong>示例 2:</strong></p>
 
<pre>
<strong>输入:</strong> <em><strong>k</strong></em> = 3, <em><strong>n</strong></em> = 9
<strong>输出:</strong> [[1,2,6], [1,3,5], [2,3,4]]
<strong>解释:
</strong>1 + 2 + 6 = 9
1 + 3 + 5 = 9
2 + 3 + 4 = 9
没有其他符合的组合了。</pre>
 
<p><strong>示例 3:</strong></p>
 
<pre>
<strong>输入:</strong> k = 4, n = 1
<strong>输出:</strong> []
<strong>解释:</strong> 不存在有效的组合。
在[1,9]范围内使用4个不同的数字，我们可以得到的最小和是1+2+3+4 = 10，因为10 &gt; 1，没有有效的组合。
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示:</strong></p>
 
<ul>
	<li><code>2 &lt;= k &lt;= 9</code></li>
	<li><code>1 &lt;= n &lt;= 60</code></li>
</ul>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/combination-sum-iii/submissions/) | [题解](https://leetcode.cn/problems/combination-sum-iii/solution/)

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