AtCoder Grand Contest 015
C
Nuske vs Phantom Thnook
AtCoder
⌀ 2241
原题
← BD →
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Problem Statement

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Nuske has a grid with $N$ rows and $M$ columns of squares. The rows are numbered $1$ through $N$ from top to bottom, and the columns are numbered $1$ through $M$ from left to right. Each square in the grid is painted in either blue or white. If $S_{i,j}$ is $1$, the square at the $i$-th row and $j$-th column is blue; if $S_{i,j}$ is $0$, the square is white. For every pair of two blue square $a$ and $b$, there is at most one path that starts from $a$, repeatedly proceeds to an adjacent (side by side) blue square and finally reaches $b$, without traversing the same square more than once.

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Phantom Thnook, Nuske's eternal rival, gives $Q$ queries to Nuske. The $i$-th query consists of four integers $x_{i,1}$, $y_{i,1}$, $x_{i,2}$ and $y_{i,2}$ and asks him the following: when the rectangular region of the grid bounded by (and including) the $x_{i,1}$-th row, $x_{i,2}$-th row, $y_{i,1}$-th column and $y_{i,2}$-th column is cut out, how many connected components consisting of blue squares there are in the region?

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Process all the queries.

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Constraints

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  • $1 ≤ N,M ≤ 2000$
  • $1 ≤ Q ≤ 200000$
  • $S_{i,j}$ is either $0$ or $1$.
  • $S_{i,j}$ satisfies the condition explained in the statement.
  • $1 ≤ x_{i,1} ≤ x_{i,2} ≤ N(1 ≤ i ≤ Q)$
  • $1 ≤ y_{i,1} ≤ y_{i,2} ≤ M(1 ≤ i ≤ Q)$
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Input

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The input is given from Standard Input in the following format:

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N M Q
S_{1,1}..S_{1,M}
:
S_{N,1}..S_{N,M}
x_{1,1} y_{i,1} x_{i,2} y_{i,2}
:
x_{Q,1} y_{Q,1} x_{Q,2} y_{Q,2}

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Output

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For each query, print the number of the connected components consisting of blue squares in the region.

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样例

Input #1
3 4 4
1101
0110
1101
1 1 3 4
1 1 3 1
2 2 3 4
1 2 2 4
Output #1
3
2
2
2
![image](https://atcoder.jp/img/agc015/7aa4a2252f50a19fc18e0cec01368a2a.png) In the first query, the whole grid is specified. There are three components consisting of blue squares, and thus $3$ should be printed. In the second query, the region within the red frame is specified. There are two components consisting of blue squares, and thus $2$ should be printed. Note that squares that belong to the same component in the original grid may belong to different components.
Input #2
5 5 6
11010
01110
10101
11101
01010
1 1 5 5
1 2 4 5
2 3 3 4
3 3 3 3
3 1 3 5
1 1 3 4
Output #2
3
2
1
1
3
2
题目信息
题号
agc015_c
时间限制
4 s
内存限制
256 MB

题面与样例版权归 AtCoder 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。