Loserinlife's blog

Sum of kth smallest distances.
By Loserinlife, history, 14 months ago, In English

Given a n * m matrix of 0s and 1s. For each square,find the sum of Manhattan distances from that square to the first kth nearest 1s.

(Distance to closest 1 + distance to second closest 1 + ...)

n, m <= 2000

k <= n * m

There are at least k ones in the matrix. Thanks!

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14 months ago, # |
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https://atcoder.jp/contests/abc233/tasks/abc233_h?fbclid=IwAR2FvFmPdn0ly71SBs5cYpRKmZSzmgFxtjpq_JVJHLpME48HhLJbQOJvwx0

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    14 months ago, # ^ |
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    I think it's a bit different because I want the sum of the first kth distances, not only the kth.

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      14 months ago, # ^ |
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      the idea is a bit similar, in order to calculate the sum of the first kth distance, we need to consider 4 cases to handle |x1 — x2| + |y1 — y2|.

      (x1 > x2, y1 > y2)

      (x1 < x2, y1 < y2)

      (x1 > x2, y1 < y2)

      (x1 < x2, y1 > y2)

      we can see that we can divide the square into 4 seperate smaller squares to handle that.

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14 months ago, # |
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Can you provide the source of this task? I think I have something quite close to solving the task but I need some research on it

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