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42 lines
1.3 KiB
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42 lines
1.3 KiB
HTML
<p>Given an array of <strong>distinct</strong> integers <code>nums</code> and a target integer <code>target</code>, return <em>the number of possible combinations that add up to</em> <code>target</code>.</p>
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<p>The test cases are generated so that the answer can fit in a <strong>32-bit</strong> integer.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [1,2,3], target = 4
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<strong>Output:</strong> 7
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<strong>Explanation:</strong>
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The possible combination ways are:
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(1, 1, 1, 1)
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(1, 1, 2)
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(1, 2, 1)
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(1, 3)
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(2, 1, 1)
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(2, 2)
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(3, 1)
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Note that different sequences are counted as different combinations.
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</pre>
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<p><strong>Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [9], target = 3
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<strong>Output:</strong> 0
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>1 <= nums.length <= 200</code></li>
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<li><code>1 <= nums[i] <= 1000</code></li>
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<li>All the elements of <code>nums</code> are <strong>unique</strong>.</li>
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<li><code>1 <= target <= 1000</code></li>
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</ul>
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<p> </p>
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<p><strong>Follow up:</strong> What if negative numbers are allowed in the given array? How does it change the problem? What limitation we need to add to the question to allow negative numbers?</p>
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