摘要：
Ugly number is a number that only have factors 2, 3and 5. Design an algorithm to find the nth ugly number. The first 10 ugly numbers are 1, 2, 3, 4, 5 阅读全文
摘要：
Implement a stack with min() function, which will return the smallest number in the stack. It should support push, pop and min operation all in O(1) c 阅读全文