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Formatted question description: https://leetcode.ca/all/2579.html
2579. Count Total Number of Colored Cells
Description
There exists an infinitely large two-dimensional grid of uncolored unit cells. You are given a positive integer n
, indicating that you must do the following routine for n
minutes:
- At the first minute, color any arbitrary unit cell blue.
- Every minute thereafter, color blue every uncolored cell that touches a blue cell.
Below is a pictorial representation of the state of the grid after minutes 1, 2, and 3.
Return the number of colored cells at the end of n
minutes.
Example 1:
Input: n = 1 Output: 1 Explanation: After 1 minute, there is only 1 blue cell, so we return 1.
Example 2:
Input: n = 2 Output: 5 Explanation: After 2 minutes, there are 4 colored cells on the boundary and 1 in the center, so we return 5.
Constraints:
1 <= n <= 105
Solutions
-
class Solution { public long coloredCells(int n) { return 2L * n * (n - 1) + 1; } }
-
class Solution { public: long long coloredCells(int n) { return 2LL * n * (n - 1) + 1; } };
-
class Solution: def coloredCells(self, n: int) -> int: return 2 * n * (n - 1) + 1
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func coloredCells(n int) int64 { return int64(2*n*(n-1) + 1) }
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function coloredCells(n: number): number { return 2 * n * (n - 1) + 1; }
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impl Solution { pub fn colored_cells(n: i32) -> i64 { 2 * (n as i64) * (n as i64 - 1) + 1 } }