Max Even

AtCoder

IDabc272_c

Time2000ms

Memory256MB

Difficulty—

You are given a sequence $A=(A_1,A_2,\ldots,A_N)$ of length $N$ consisting of non-negative integers. Determine if there is an even number represented as the sum of two different elements of $A$. If it exists, find the maximum such number. ## Constraints * $2\leq N \leq 2\times 10^5$ * $0\leq A_i\leq 10^9$ * The elements of $A$ are distinct. * All values in the input are integers. ## Input The input is given from Standard Input in the following format: $N$ $A_1$ $A_2$ $\ldots$ $A_N$ [samples]

Samples

Input #1

3
2 3 4

Output #1

6

The values represented as the sum of two distinct elements of $A$ are $5$, $6$, and $7$. We have an even number here, and the maximum is $6$.

Input #2

2
1 0

Output #2

\-1

The value represented as the sum of two distinct elements of $A$ is $1$. We have no even number here, so `-1` should be printed.

API Response (JSON)

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    "platform": "AtCoder",
    "limit": {
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      "memory_limit": 262144
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    "difficulty": "None",
    "is_remote": true,
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      "statement_type": "Markdown",
      "content": "You are given a sequence $A=(A_1,A_2,\\ldots,A_N)$ of length $N$ consisting of non-negative integers.\nDetermine if there is an even number represented as the sum of two different elements of $A$. If it...",
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      "language": "English"
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