Codeforces Round 626 (Div. 2, based on Moscow Open Olympiad in Informatics)
A
Even Subset Sum Problem
Codeforces
800
原题
←B →
翻译中…

You are given an array $a$ consisting of $n$ positive integers. Find a non-empty subset of its elements such that their sum is even (i.e. divisible by $2$) or determine that there is no such subset.

翻译中…

Both the given array and required subset may contain equal values.

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Input

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The first line contains a single integer $t$ ($1 \leq t \leq 100$), number of test cases to solve. Descriptions of $t$ test cases follow.

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A description of each test case consists of two lines. The first line contains a single integer $n$ ($1 \leq n \leq 100$), length of array $a$.

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The second line contains $n$ integers $a_1, a_2, \ldots, a_n$ ($1 \leq a_i \leq 100$), elements of $a$. The given array $a$ can contain equal values (duplicates).

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Output

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For each test case output $-1$ if there is no such subset of elements. Otherwise output positive integer $k$, number of elements in the required subset. Then output $k$ distinct integers ($1 \leq p_i \leq n$), indexes of the chosen elements. If there are multiple solutions output any of them.

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Note

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There are three test cases in the example.

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In the first test case, you can choose the subset consisting of only the second element. Its sum is $4$ and it is even.

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In the second test case, there is only one non-empty subset of elements consisting of the first element, however sum in it is odd, so there is no solution.

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In the third test case, the subset consisting of all array's elements has even sum.

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样例

Input #1
3
3
1 4 3
1
15
2
3 5
Output #1
1
2
-1
2
1 2
InputCopy OutputCopy
题目信息
题号
1323A
时间限制
1 s
内存限制
512 MB
标签
暴力
动态规划
贪心
模拟

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。