Editorial for LCC '23 Contest 1 J4 - Candy Plan - MCPT: Mackenzie Competitive Programming Team

Editorial for LCC '23 Contest 1 J4 - Candy Plan

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Author: AngelsandDevsLOL

This problem wants you to rotate an $N$ ~N~ by $N$ ~N~ grid by K degrees clockwise and print it. Knowing that K is a multiple of 90, we simply need to rotate the array by 90 degrees clockwise K / 90 times. If we want to rotate the array by 270, we rotate it by 90 degrees 3 times. Notice that when an array is rotated, every element will also be moved.

Let $(x, y)$ ~(x, y)~ be an element in $array[x][y]$ ~array[x][y]~. The following directions assume that the array is 0-indexed:

When K = 0, there is no rotation.

When K = 90, or when the array is rotated once, every element $(x, y)$ ~(x, y)~ will go to $(y, N - x - 1)$ ~(y, N - x - 1)~.

When K = 180, every element $(x, y)$ ~(x, y)~ will go to $(N - x - 1, N - y - 1)$ ~(N - x - 1, N - y - 1)~.

When K = 270, every element $(x, y)$ ~(x, y)~ will go to $(N - y - 1, x)$ ~(N - y - 1, x)~.

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