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Valid Perfect Square (E) 题目 Given a positive integer num, write a function which returns True if num is a perfect square else False. Follow up: Do not 阅读全文
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Insert Interval (H) 题目 Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary). You may assume that th 阅读全文
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Ugly Number II (M) 题目 Write a program to find the n-th ugly number. Ugly numbers are positive numbers whose prime factors only include 2, 3, 5. Exampl 阅读全文