Codeforces Round 542 [Alex Lopashev Thanks-Round] (Div. 2)
C
Connect
Codeforces
1400
原题
← BD1 →
翻译中…

Alice lives on a flat planet that can be modeled as a square grid of size $n \times n$, with rows and columns enumerated from $1$ to $n$. We represent the cell at the intersection of row $r$ and column $c$ with ordered pair $(r, c)$. Each cell in the grid is either land or water.

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image An example planet with $n = 5$. It also appears in the first sample test.

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Alice resides in land cell $(r_1, c_1)$. She wishes to travel to land cell $(r_2, c_2)$. At any moment, she may move to one of the cells adjacent to where she is—in one of the four directions (i.e., up, down, left, or right).

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Unfortunately, Alice cannot swim, and there is no viable transportation means other than by foot (i.e., she can walk only on land). As a result, Alice's trip may be impossible.

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To help Alice, you plan to create at most one tunnel between some two land cells. The tunnel will allow Alice to freely travel between the two endpoints. Indeed, creating a tunnel is a lot of effort: the cost of creating a tunnel between cells $(r_s, c_s)$ and $(r_t, c_t)$ is $(r_s-r_t)^2 + (c_s-c_t)^2$.

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For now, your task is to find the minimum possible cost of creating at most one tunnel so that Alice could travel from $(r_1, c_1)$ to $(r_2, c_2)$. If no tunnel needs to be created, the cost is $0$.

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Input

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The first line contains one integer $n$ ($1 \leq n \leq 50$) — the width of the square grid.

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The second line contains two space-separated integers $r_1$ and $c_1$ ($1 \leq r_1, c_1 \leq n$) — denoting the cell where Alice resides.

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The third line contains two space-separated integers $r_2$ and $c_2$ ($1 \leq r_2, c_2 \leq n$) — denoting the cell to which Alice wishes to travel.

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Each of the following $n$ lines contains a string of $n$ characters. The $j$-th character of the $i$-th such line ($1 \leq i, j \leq n$) is 0 if $(i, j)$ is land or 1 if $(i, j)$ is water.

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It is guaranteed that $(r_1, c_1)$ and $(r_2, c_2)$ are land.

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Output

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Print an integer that is the minimum possible cost of creating at most one tunnel so that Alice could travel from $(r_1, c_1)$ to $(r_2, c_2)$.

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Note

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In the first sample, a tunnel between cells $(1, 4)$ and $(4, 5)$ should be created. The cost of doing so is $(1-4)^2 + (4-5)^2 = 10$, which is optimal. This way, Alice could walk from $(1, 1)$ to $(1, 4)$, use the tunnel from $(1, 4)$ to $(4, 5)$, and lastly walk from $(4, 5)$ to $(5, 5)$.

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In the second sample, clearly a tunnel between cells $(1, 3)$ and $(3, 1)$ needs to be created. The cost of doing so is $(1-3)^2 + (3-1)^2 = 8$.

翻译中…

样例

Input #1
5
1 1
5 5
00001
11111
00111
00110
00110
Output #1
10
InputCopy OutputCopy
Input #2
3
1 3
3 1
010
101
010
Output #2
8
InputCopy OutputCopy
题目信息
题号
1130C
时间限制
1 s
内存限制
256 MB
标签
暴力
DFS 及类似
并查集

题面与样例版权归 Codeforces 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。