Even Frequency Check

CountingHash TableString

Given an array of integers, determine if all the integers have an even frequency in the array. Return 'Yes' if every integer appears an even number of times, otherwise return 'No'.

Example 1

Input

[
  2,
  4,
  4,
  2
]

Output

Yes

Explanation. Both 2 and 4 appear twice in the array, which is an even count, so the output is 'Yes'.

Example 2

Input

[
  3,
  3,
  1,
  1,
  2,
  2
]

Output

Yes

Explanation. 3, 1, and 2 all have frequencies of two, which is even.

Example 3

Input

[
  1,
  2,
  3,
  4,
  5
]

Output

Explanation. Each number appears exactly once, which is not an even count.

Example 4

Input

Output

Yes

Explanation. 10 appears six times, which is an even count.

Example 5

Input

[
  7,
  8,
  8,
  7,
  7
]

Output

Explanation. 7 appears three times and 8 appears twice, 7 does not meet the even frequency requirement.

Follow-up: How would you optimize your solution for a very large input array?

Constraints:

1. The input array will contain at least one integer.\n2. All integers in the array will be positive.

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