P8740 [Lanqiao Cup 2021 NOI Qualifier A] Fill-in-the-Blank Problems

## Task A: Cards ### Problem Description Xiao Lan has many digit cards. Each card has a digit from $0$ to $9$ on it. Xiao Lan plans to use these cards to form some numbers. He wants to form positive integers starting from $1$. After forming a number, he keeps it, and the cards used for it cannot be used to form other numbers. Xiao Lan wants to know how far he can form numbers starting from $1$. For example, when Xiao Lan has $30$ cards, with $3$ cards for each digit from $0$ to $9$, Xiao Lan can form $1$ to $10$. But when forming $11$, he has only one card with digit $1$ left, which is not enough to form $11$. Now Xiao Lan has $2021$ cards for each digit from $0$ to $9$, a total of $20210$ cards. Up to what number can Xiao Lan form starting from $1$? Hint: It is recommended to solve this problem using computer programming. ### Answer Submission This is a fill-in-the-blank problem. You only need to compute the result and submit it. The result of this problem is an integer. When submitting, only fill in this integer. Any extra content will result in no score. ## Task B: Lines ### Problem Description In the Cartesian coordinate system, two points determine a line. If multiple points lie on the same line, then the line determined by any two of these points is the same line. Given $2 \times 3$ lattice points on the plane $\{(x,y) \mid 0 \leq x

Input one uppercase letter, indicating which task it is.

According to the input task letter, output the answer for the corresponding task.

Answer template for reference. ```cpp #include using namespace std; int main() { string ans [] = { "The answer of task A", // Replace the content in double quotes with the answer to task A. "The answer of task B", // Replace the content in double quotes with the answer to task B. "The answer of task C", // Replace the content in double quotes with the answer to task C. "The answer of task D", // Replace the content in double quotes with the answer to task D. "The answer of task E", // Replace the content in double quotes with the answer to task E. }; char T; cin >> T; cout