CSES - Forest Queries
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Gửi bài giải
Điểm:
1,00 (OI)
Giới hạn thời gian:
1.0s
Giới hạn bộ nhớ:
512M
Input:
stdin
Output:
stdout
Nguồn bài:
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Ngôn ngữ cho phép
C, C++, Java, Kotlin, Pascal, PyPy, Python, Scratch
You are given an ~n \times n~ grid representing the map of a forest. Each square is either empty or contains a tree. The upper-left square has coordinates ~(1,1)~, and the lower-right square has coordinates ~(n,n)~.
Your task is to process ~q~ queries of the form: how many trees are inside a given rectangle in the forest?
Input
- The first input line has two integers ~n~ and ~q~: the size of the forest and the number of queries.
Then, there are ~n~ lines describing the forest. Each line has ~n~ characters: . is an empty square and * is a tree.
Finally, there are ~q~ lines describing the queries. Each line has four integers ~y\_1~, ~x\_1~, ~y\_2~, ~x\_2~ corresponding to the corners of a rectangle.
Output
- Print the number of trees inside each rectangle.
Constraints
- ~1 \le n \le 1000~
- ~1 \le q \le 2 \cdot 10^5~
- ~1 \le y\_1 \le y\_2 \le n~
- ~1 \le x\_1 \le x\_2 \le n~
Example Input
4 3
.*..
*.**
**..
****
2 2 3 4
3 1 3 1
1 1 2 2
Example Output
3
1
2
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