{ "data": { "question": { "questionId": "377", "questionFrontendId": "377", "boundTopicId": null, "title": "Combination Sum IV", "titleSlug": "combination-sum-iv", "content": "

Given an array of distinct integers nums and a target integer target, return the number of possible combinations that add up to target.

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The test cases are generated so that the answer can fit in a 32-bit integer.

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Example 1:

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\nInput: nums = [1,2,3], target = 4\nOutput: 7\nExplanation:\nThe possible combination ways are:\n(1, 1, 1, 1)\n(1, 1, 2)\n(1, 2, 1)\n(1, 3)\n(2, 1, 1)\n(2, 2)\n(3, 1)\nNote that different sequences are counted as different combinations.\n
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Example 2:

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\nInput: nums = [9], target = 3\nOutput: 0\n
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Constraints:

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Follow up: 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?

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