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I am encountering a problem that I am unable to solve:↵
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I need to print the order from fold l to r of folding up and down a piece of paper after \( n \) times of performing two folds alternately left and right. Please use 'D' for Down and 'U' for Up.↵
Input: n, l and r.↵
For example:↵
Input: 2 1 3↵
Output: DDU↵
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Note that folding left means folding the right edge over the left edge, and folding right means folding the left edge over the right edge.↵
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I have a rough idea of using a deque to store the order, but I can't figure out the exact algorithm for this problem.↵
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Can you provide some hints?↵
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Thank you!↵
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Edit: Also 1<=n<=60, 1<=l<r<=2^n and r-l<=10^6
