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27 lines
1.2 KiB
HTML
27 lines
1.2 KiB
HTML
<!DOCTYPE html>
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<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
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<h1>1140. Look-and-say Sequence (20)</h1>
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<div id="problemContent">
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<p><b>Look-and-say sequence</b> is a sequence of integers as the following:
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</p><pre>
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D, D1, D111, D113, D11231, D112213111, ...
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</pre><p>
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where D is in [0, 9] except 1. The (n+1)st number is a kind of description of the nth number. For example, the 2nd number means that there is one D in the 1st number, and hence it is D1; the 2nd number consists of one D (corresponding to D1) and one 1 (corresponding to 11), therefore the 3rd number is D111; or since the 4th number is D113, it consists of one D, two 1's, and one 3, so the next number must be D11231. This definition works for D = 1 as well. Now you are supposed to calculate the Nth number in a look-and-say sequence of a given digit D.
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</p>
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<p><b>
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Input Specification:
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</b></p>
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<p>Each input file contains one test case, which gives D (in [0, 9]) and a positive integer N (<=40), separated by a space.
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</p>
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<p><b>
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Output Specification:
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</b></p>
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<p>Print in a line the Nth number in a look-and-say sequence of D.
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</p>
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<b>Sample Input:</b><pre>
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1 8
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</pre>
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<b>Sample Output:</b><pre>
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1123123111
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</pre>
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</div> |