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Eva loves to collect coins from all over the universe, including some other planets like Mars. One day she visited a universal shopping mall which cou 阅读全文
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The task is simple: given any positive integer N, you are supposed to count the total number of 1's in the decimal form of the integers from 1 to N. F 阅读全文
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Given two strings S1 and S2, S=S1−S2 is defined to be the remaining string after taking all the characters in S2 from S1. Your task 阅读全文
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Given a stack which can keep M numbers at most. Push N numbers in the order of 1, 2, 3, ..., N and pop randomly. You are supposed to tell if a given s 阅读全文
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A linked list consists of a series of structures, which are not necessarily adjacent in memory. We assume that each structure contains an integer key 阅读全文
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Given a non-empty tree with root R, and with weight Wi assigned to each tree node Ti. The weight of a path from R to L is defined to be the sum 阅读全文
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Behind the scenes in the computer's memory, color is always talked about as a series of 24 bits of information for each pixel. In an image, the color 阅读全文
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Forbes magazine publishes every year its list of billionaires based on the annual ranking of the world's wealthiest people. Now you are supposed to si 阅读全文
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Mice and Rice is the name of a programming contest in which each programmer must write a piece of code to control the movements of a mouse in a given 阅读全文
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Stack is one of the most fundamental data structures, which is based on the principle of Last In First Out (LIFO). The basic operations include Push ( 阅读全文