P1752 Ordering Dishes

There are $n$ people who come to a restaurant to order dishes. The restaurant has $m$ dishes in total, and each dish has two attributes: tastiness and price. These $n$ people come once every week, and each time each person will order at most one dish or none. Among these $n$ people, $p$ people are picky; they can only accept dishes with tastiness greater than or equal to a certain value. Another $q$ people are poor; they can only order dishes with price less than or equal to a certain value. Now please compute: what is the minimum number of weeks they need to come so that it is possible to have ordered all dishes at least once?

- Line $1$: four positive integers $n, m, p, q$. - Lines $2 \sim m+1$: each line contains two numbers, the tastiness and the price of a dish. - Line $m+2$: $p$ numbers, the lower bounds of acceptable tastiness for each of the $p$ picky people. - Line $m+3$: $q$ numbers, the upper bounds of acceptable price for each of the $q$ poor people.

Output a single number: the minimum number of weeks needed. If it is impossible to have all dishes ordered at least once no matter how many weeks they come, output $-1$.

Constraints and Conventions: - For $20\%$ of the testdata, $m \le 20$. - For $40\%$ of the testdata, $m \le 2000$. - For $100\%$ of the testdata, $p+q \le n \le 50000$, $m \le 200000$. Translated by ChatGPT 5