U517656 「Cfz Round 5」Non-breath Oblige (English)

[Chinese Statement](https://www.luogu.com.cn/problem/P11485). **You must submit your code at the Chinese version of the statement.** --- それぞれの好きを守るため To protect our respective beloved ones, 君と防空壕で呼吸する We breathe together in the air-raid shelter.

Given three integers $n, s, t$, where $0 \le s, t < 2^n$. You can perform several operations. In each operation, you can choose a non-negative integer $x$ and modify the value of $s$ to $x$, subject to the following conditions: - It must satisfy $x < 2^n$; - It must satisfy $s \cup x = 2^n - 1$, where $\cup$ denotes the bitwise OR operation; - The cost you need to pay is $s \oplus x$, where $\oplus$ denotes the bitwise XOR operation. You need to find the minimum sum of costs required to make $s = t$.

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#### Sample Explanation #1 For the first test case, since $1 \cup 2 = 3$, you can directly change the value of $s$ from $1$ to $2$, with a cost of $1 \oplus 2$, which is $3$. It can be proven that the minimum sum of costs required to make $s = t$ is $3$. For the second test case, no operation is needed to satisfy $s = t$. #### Constraints For all test cases, it is guaranteed that: - $1 \le T \le 100$; - $1 \le n \le 30$; - $0 \le s, t < 2^n$. **Subtasks are used in this task.** - Subtask 0 (12 points): $s = t$. - Subtask 1 (15 points): $n = 1$. - Subtask 2 (20 points): $s + t = 2^n - 1$. - Subtask 3 (10 points): $t = 2^n - 1$. - Subtask 4 (18 points): $t = 0$. - Subtask 5 (25 points): No further restrictions.