Project Notes

Combination Sum

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Description

tab: English
 
<p>Given an array of <strong>distinct</strong> integers <code>candidates</code> and a target integer <code>target</code>, return <em>a list of all <strong>unique combinations</strong> of </em><code>candidates</code><em> where the chosen numbers sum to </em><code>target</code><em>.</em> You may return the combinations in <strong>any order</strong>.</p>
 
<p>The <strong>same</strong> number may be chosen from <code>candidates</code> an <strong>unlimited number of times</strong>. Two combinations are unique if the <span data-keyword="frequency-array">frequency</span> of at least one of the chosen numbers is different.</p>
 
<p>The test cases are generated such that the number of unique combinations that sum up to <code>target</code> is less than <code>150</code> combinations for the given input.</p>
 
<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>
 
<pre>
<strong>Input:</strong> candidates = [2,3,6,7], target = 7
<strong>Output:</strong> [[2,2,3],[7]]
<strong>Explanation:</strong>
2 and 3 are candidates, and 2 + 2 + 3 = 7. Note that 2 can be used multiple times.
7 is a candidate, and 7 = 7.
These are the only two combinations.
</pre>
 
<p><strong class="example">Example 2:</strong></p>
 
<pre>
<strong>Input:</strong> candidates = [2,3,5], target = 8
<strong>Output:</strong> [[2,2,2,2],[2,3,3],[3,5]]
</pre>
 
<p><strong class="example">Example 3:</strong></p>
 
<pre>
<strong>Input:</strong> candidates = [2], target = 1
<strong>Output:</strong> []
</pre>
 
<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>
 
<ul>
	<li><code>1 &lt;= candidates.length &lt;= 30</code></li>
	<li><code>2 &lt;= candidates[i] &lt;= 40</code></li>
	<li>All elements of <code>candidates</code> are <strong>distinct</strong>.</li>
	<li><code>1 &lt;= target &lt;= 40</code></li>
</ul>
 
 
 
---
 
[submissions](https://leetcode.com/problems/combination-sum/submissions/) | [solutions](https://leetcode.com/problems/combination-sum/solutions/)
 
 
tab: 中文
 
<p>给你一个 <strong>无重复元素</strong> 的整数数组&nbsp;<code>candidates</code> 和一个目标整数&nbsp;<code>target</code>&nbsp;，找出&nbsp;<code>candidates</code>&nbsp;中可以使数字和为目标数&nbsp;<code>target</code> 的 所有<em>&nbsp;</em><strong>不同组合</strong> ，并以列表形式返回。你可以按 <strong>任意顺序</strong> 返回这些组合。</p>
 
<p><code>candidates</code> 中的 <strong>同一个</strong> 数字可以 <strong>无限制重复被选取</strong> 。如果至少一个数字的被选数量不同，则两种组合是不同的。&nbsp;</p>
 
<p>对于给定的输入，保证和为&nbsp;<code>target</code> 的不同组合数少于 <code>150</code> 个。</p>
 
<p>&nbsp;</p>
 
<p><strong>示例&nbsp;1：</strong></p>
 
<pre>
<strong>输入：</strong>candidates = [2,3,6,7], target = 7
<strong>输出：</strong>[[2,2,3],[7]]
<strong>解释：</strong>
2 和 3 可以形成一组候选，2 + 2 + 3 = 7 。注意 2 可以使用多次。
7 也是一个候选， 7 = 7 。
仅有这两种组合。</pre>
 
<p><strong>示例&nbsp;2：</strong></p>
 
<pre>
<strong>输入: </strong>candidates = [2,3,5], target = 8
<strong>输出: </strong>[[2,2,2,2],[2,3,3],[3,5]]</pre>
 
<p><strong>示例 3：</strong></p>
 
<pre>
<strong>输入: </strong>candidates = [2], target = 1
<strong>输出: </strong>[]
</pre>
 
<p>&nbsp;</p>
 
<p><strong>提示：</strong></p>
 
<ul>
	<li><code>1 &lt;= candidates.length &lt;= 30</code></li>
	<li><code>2 &lt;= candidates[i] &lt;= 40</code></li>
	<li><code>candidates</code> 的所有元素 <strong>互不相同</strong></li>
	<li><code>1 &lt;= target &lt;= 40</code></li>
</ul>
 
 
 
---
 
[提交记录](https://leetcode.cn/problems/combination-sum/submissions/) | [题解](https://leetcode.cn/problems/combination-sum/solution/)

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