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问题： Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return –321 Have you thought about this? Here are some good questions to ask before coding. Bonus p... 阅读全文
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问题： Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical and the nodes have the same value. 分析： ... 阅读全文
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问题： Given an array of integers, every element appears twice except for one. Find that single one. Note: Your algorithm should have a linear runtime complexity. Could you implement it without us... 阅读全文
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问题： You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Follow up: Could you do this in-place? 分析： 二维数组a[n][n]顺时针旋转90度，要解决这个问题，无疑，第一件事儿就... 阅读全文