P8431 "WHOI-2" Comet Honeymoon

 After watching the intro of this MV, you should know what the heck $f$ is (just kidding).

Define $f(x)$ as the number formed by reversing the digits of $x$. For example: - $f(12323)=32321$. - $f(114514)=415411$. - $f(250)=52$. Given an integer $n$, find the largest $k$ such that for every positive integer $m$ in the interval $[1,k]$, we have $f(m)\leq n$.

**This problem has multiple test cases.** The first line contains a positive integer $T$, the number of test cases. Each of the next $T$ lines contains a positive integer $n$.

Output $T$ lines, one for each test case, containing the answer.

For sample test $1$: $f(1)=1,f(2)=2,f(3)=3,f(4)=4,f(5)=5,f(6)=6,f(7)=7,f(8)=8,f(9)=9,f(10)=1,f(11)=11,f(12)=21$. Therefore, the maximum $k$ is $11$. --- **This problem uses bundled testdata.** - $\text{subtask1(10pts)}:1\leq T,n\leq10^3$. - $\text{subtask2(30pts)}:1\leq n\leq10^6$. - $\text{subtask3(40pts)}:1\leq n\leq10^9$. - $\text{subtask4(20pts)}:$ No special constraints. For $100\%$ of the data, $1\leq T\leq10^5,1\leq n\leq10^{18}$. Hint: `unsigned long long` can store natural numbers from $0$ to $18,446,744,073,709,551,615(2^{64}-1)$. Translated by ChatGPT 5