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Given a 2D board and a word, find if the word exists in the grid. The word can be constructed from letters of sequentially adjacent cell, where "adjac 阅读全文
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Follow up for "Search in Rotated Sorted Array":What if duplicates are allowed? Would this affect the run-time complexity? How and why? Write a functio 阅读全文
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Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e.,0 1 2 4 5 6 7might become4 5 6 7 0 1 2). You are given a target value 阅读全文
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Given two integers n and k, return all possible combinations of k numbers out of 1 ... n. For example,If n = 4 and k = 2, a solution is: 题意：给定1...n个数， 阅读全文