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Primitive Primes : two integers are coprime if their GCD is 1. If a number A is not divisible by another prime number P, then A and P are guranteed to 阅读全文
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Given a m x n grid. Each cell of the grid has a sign pointing to the next cell you should visit if you are currently in this cell. The sign of grid[i] 阅读全文
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An interesting problem using suffix sum. For each wrong tries that is correct until after index p[i], we add 1 to cnt[p[i]]. This represents that all 阅读全文
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Problem Statement Link Clarification: The problem states that for each pair of points, we consider the minimum possible distance over any possible mom 阅读全文
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Given an array A of positive integers, call a (contiguous, not necessarily distinct) subarray of A good if the number of different integers in that su 阅读全文
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We are given an array A of N lowercase letter strings, all of the same length. Now, we may choose any set of deletion indices, and for each string, we 阅读全文
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You have some sticks with positive integer lengths. You can connect any two sticks of lengths X and Y into one stick by paying a cost of X + Y. You pe 阅读全文
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Given a non-empty 2D array grid of 0's and 1's, an island is a group of 1's (representing land) connected 4-directionally (horizontal or vertical.) Yo 阅读全文
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Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two 阅读全文
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Median is the middle value in an ordered integer list. If the size of the list is even, there is no middle value. So the median is the mean of the two 阅读全文