#39

Combination Sum

medium· Backtrackingruns: 0

Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum to target. The same number may be chosen an unlimited number of times. Two combinations are unique if the frequency of at least one chosen number differs.

wpm 0acc 100%time 0:000 / 589

class Solution:
    def combinationSum(
        self, candidates: list[int], target: int
    ) -> list[list[int]]:
        result = []
        path = []

        def backtrack(start: int, remaining: int) -> None:
            if remaining == 0:
                result.append(path[:])
                return
            if remaining < 0:
                return
            for i in range(start, len(candidates)):
                path.append(candidates[i])
                backtrack(i, remaining - candidates[i])
                path.pop()

        backtrack(0, target)
        return result

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