摘要：
Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16 ...) which sum to n. For example, given n = 12, 阅读全文
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Given a triangle, find the minimum path sum from top to bottom. Each step you may move to adjacent numbers on the row below. For example, given the fo 阅读全文
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Given n, how many structurally unique BST's (binary search trees) that store values 1...n? For example, given n = 3, there are a total of 5 unique BST 阅读全文
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1. Maximum Subarray (#53) Find the contiguous subarray within an array (containing at least one number) which has the largest sum. For example, given 阅读全文