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226. Invert Binary Tree Invert a binary tree. to 阅读全文
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104. Maximum Depth of Binary Tree Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from th 阅读全文
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258. Add Digits Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the 阅读全文
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292. Nim Game(C++) You are playing the following Nim Game with your friend: There is a heap of stones on the table, each time one of you take turns to 阅读全文
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344. Reverse String Write a function that takes a string as input and returns the string reversed. Example: Given s = "hello", return "olleh". 题目大意： 字 阅读全文
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263. Ugly Number Write a program to check whether a given number is an ugly number. Ugly numbers are positive numbers whose prime factors only include 阅读全文