62 lines
1.5 KiB
Markdown
62 lines
1.5 KiB
Markdown
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# B. Following the String
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[Codeforces.com](https://codeforces.com/contest/1927/problem/B)
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Polycarp lost the string s of length n consisting of lowercase Latin letters, but he still has its trace.
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The trace of the string s
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is an array a of n integers, where ai is the number of such indices j (j<i) that si=sj. For example, the trace of the string abracadabra is the array `[0,0,0,1,0,2,0,3,1,1,4]`.
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Given a trace of a string, find any string s from which it could have been obtained. The string s should consist only of lowercase Latin letters a-z.
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## Input
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The first line of the input contains a single integer t
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(1 ≤ t ≤ 10^4) — the number of test cases. Then the descriptions of the test cases follow.
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The first line of each test case contains a single integer n
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(1 ≤ n ≤ 2*10^5) — the length of the lost string.
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The second line of each test case contains n
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integers a1,a2,…,an (0 ≤ ai < n) — the trace of the string. It is guaranteed that for the given trace, there exists a suitable string s.
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It is guaranteed that the sum of n over all test cases does not exceed 2*10^5.
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## Output
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For each test case, output a string s
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that corresponds to the given trace. If there are multiple such strings s, then output any of them.
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The string s should consist of lowercase Latin letters a-z.
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It is guaranteed that for each test case, a valid answer exists.
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## Example
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Input
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```
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5
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11
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0 0 0 1 0 2 0 3 1 1 4
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10
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0 0 0 0 0 1 0 1 1 0
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1
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0
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8
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0 1 2 3 4 5 6 7
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8
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0 0 0 0 0 0 0 0
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```
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Output
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```
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abracadabra
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codeforces
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a
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aaaaaaaa
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dijkstra
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```
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