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Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. N 阅读全文
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You are given a binary tree in which each node contains an integer value. Find the number of paths that sum to a given value. The path does not need t 阅读全文
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Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be 阅读全文
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Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numb 阅读全文
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Given a set of candidate numbers (candidates) (without duplicates) and a target number (target), find all unique combinations in candidates where the 阅读全文
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Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum. Example: Foll 阅读全文
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Given a string containing digits from 2-9 inclusive, return all possible letter combinations that the number could represent. A mapping of digit to le 阅读全文