A. Vasya And Password
题目描述
Vasya came up with a password to register for EatForces — a string $s$ . The password in EatForces should be a string, consisting of lowercase and uppercase Latin letters and digits.
But since EatForces takes care of the security of its users, user passwords must contain at least one digit, at least one uppercase Latin letter and at least one lowercase Latin letter. For example, the passwords abaCABA12
, Z7q
and 3R24m
are valid, and the passwords qwerty
, qwerty12345
and Password
are not.
A substring of string $s$ is a string $x = s_l s_{l + 1} \cdots s_{l + len  1} (1 \le l \le s, 0 \le len \le s  l + 1)$ . $len$ is the length of the substring. Note that the empty string is also considered a substring of $s$ , it has the length $0$.
Vasya's password, however, may come too weak for the security settings of EatForces. He likes his password, so he wants to replace some its substring with another string of the same length in order to satisfy the above conditions. This operation should be performed exactly once, and the chosen string should have the minimal possible length.
Note that the length of $s$ should not change after the replacement of the substring, and the string itself should contain only lowercase and uppercase Latin letters and digits.
输入输出格式
输入格式
The first line contains a single integer $T$ ( $1 \le T \le 100$ ) — the number of testcases.
Each of the next $T$ lines contains the initial password s ( $3 \le s \le 100$ ) , consisting of lowercase and uppercase Latin letters and digits.
Only $T = 1$ is allowed for hacks.
输出格式
For each testcase print a renewed password, which corresponds to given conditions.
The length of the replaced substring is calculated as following: write down all the changed positions. If there are none, then the length is $0$ . Otherwise the length is the difference between the first and the last changed position plus one. For example, the length of the changed substring between the passwords abcdef
$\rightarrow$ a7cdEf
is $4$ , because the changed positions are $2$ and $5$ , thus $(5  2) + 1 = 4$.
It is guaranteed that such a password always exists.
If there are several suitable passwords — output any of them.
输入输出样例
输入样例#1
1  2 
输出样例#1
1  abcD4E 
说明
In the first example Vasya's password lacks a digit, he replaces substring C
with $4$ and gets password abcD4E
. That means, he changed the substring of length $1$.
In the second example Vasya's password is ok from the beginning, and nothing has to be changed. That is the same as replacing the empty substring with another empty substring (length $0$).
题解
直接模拟.
1 

B. Relatively Prime Pairs
题目描述
You are given a set of all integers from $l$ to $r$ inclusive, $l < r$ , $(r  l + 1) \le 3 \cdot 10^5$ and $(r  l)$ is always odd.
You want to split these numbers into exactly $\frac{r  l + 1}{2}$ pairs in such a way that for each pair $(i, j)$ the greatest common divisor of $i$ and $j$ is equal to $1$ . Each number should appear in exactly one of the pairs.
Print the resulting pairs or output that no solution exists. If there are multiple solutions, print any of them.
输入输出格式
输入格式
The only line contains two integers $l$ and $r$ ( $1 \le l < r \le 10^{18}$ $r  l + 1 \le 3 \cdot 10^5$, $(r  l)$ is odd).
输出格式
If any solution exists, print "YES" in the first line. Each of the next $\frac{r  l + 1}{2}$ lines should contain some pair of integers. GCD of numbers in each pair should be equal to $1$. All $(r  l + 1)$ numbers should be pairwise distinct and should have values from $l$ to $r$ inclusive.
If there are multiple solutions, print any of them.
If there exists no solution, print NO
.
输入输出样例
输入样例 #1
1  1 8 
输出样例 #1
1  YES 
题解
氵题
1 

先写到这里辣QAQ