CF1691A.Beat The Odds

Given a sequence $a_1, a_2, \ldots, a_n$, find the minimum number of elements to remove from the sequence such that after the removal, the sum of every $2$ consecutive elements is even.

给定一个序列 $a_1, a_2, \ldots, a_n$，求需要从该序列中删除的最少元素个数，使得删除后任意两个相邻元素的和均为偶数。

Each test contains multiple test cases. The first line contains a single integer $t$ ($1 \le t \le 100$) — the number of test cases. Description of the test cases follows.

The first line of each test case contains a single integer $n$ ($3 \le n \le 10^5$).

The second line of each test case contains $n$ integers $a_1, a_2,\dots,a_n$ ($1\leq a_i\leq10^9$) — elements of the sequence.

It is guaranteed that the sum of $n$ over all test cases does not exceed $10^5$.

每个测试包含多个测试用例。第一行包含一个整数 $t$（$1 \le t \le 100$），表示测试用例的数量。随后是各测试用例的描述。

每个测试用例的第一行包含一个整数 $n$（$3 \le n \le 10^5$）。

每个测试用例的第二行包含 $n$ 个整数 $a_1, a_2,\dots,a_n$（$1\leq a_i\leq10^9$），表示序列的元素。

保证所有测试用例的 $n$ 之和不超过 $10^5$。

For each test case, print a single integer — the minimum number of elements to remove from the sequence such that the sum of every $2$ consecutive elements is even.

对于每个测试用例，输出一个整数——即需要从序列中删除的最少元素个数，使得剩余序列中任意两个相邻元素的和均为偶数。

In the first test case, after removing $3$, the sequence becomes $[2,4,6,8]$. The pairs of consecutive elements are ${[2, 4], [4, 6], [6, 8]}$. Each consecutive pair has an even sum now. Hence, we only need to remove $1$ element to satisfy the condition asked.

In the second test case, each consecutive pair already has an even sum so we need not remove any element.

在第一个测试用例中，删除 $3$ 后，序列变为 $[2,4,6,8]$。相邻元素对为 ${[2, 4], [4, 6], [6, 8]}$。此时每一对相邻元素的和均为偶数。因此，我们只需删除 $1$ 个元素即可满足题目所要求的条件。

在第二个测试用例中，每一对相邻元素的和原本就是偶数，因此无需删除任何元素。