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48: Rotate Image

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`@@ -11,6 +11,7 @@ My solutions to LeetCode problems in Kotlin.`
`11`	`11`	`\| [8](https://leetcode.com/problems/string-to-integer-atoi/) \| [String to Integer (atoi)](src/main/kotlin/com/schmoczer/leetcode/_0008/StringToInteger.kt) \| Medium \|`
`12`	`12`	`\| [20](https://leetcode.com/problems/valid-parentheses/) \| [Valid Parentheses](src/main/kotlin/com/schmoczer/leetcode/_0020/ValidParentheses.kt) \| Easy \|`
`13`	`13`	`\| [42](https://leetcode.com/problems/trapping-rain-water/) \| [Trapping Rain Water](src/main/kotlin/com/schmoczer/leetcode/_0042/TrappingRainWater.kt) \| Hard \|`
	`14`	`+\| [48](https://leetcode.com/problems/rotate-image/) \| [Rotate Image](src/main/kotlin/com/schmoczer/leetcode/_0048/RotateImage.kt) \| Medium \|`
`14`	`15`	`\| [49](https://leetcode.com/problems/group-anagrams/) \| [Group Anagrams](src/main/kotlin/com/schmoczer/leetcode/_0049/GroupAnagrams.kt) \| Medium \|`
`15`	`16`	`\| [73](https://leetcode.com/problems/set-matrix-zeroes/) \| [Set Matrix Zeroes](src/main/kotlin/com/schmoczer/leetcode/_0073/SetMatrixZeroes.kt) \| Medium \|`
`16`	`17`	`\| [125](https://leetcode.com/problems/valid-palindrome/) \| [Valid Palindrome](src/main/kotlin/com/schmoczer/leetcode/_0125/ValidPalindrome.kt) \| Easy \|`

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	`1`	`+# Rotate Image`
	`2`	`+`
	`3`	+You are given an `n x n` 2D `matrix` representing an image, rotate the image by 90 degrees (clockwise).
	`4`	`+`
	`5`	`+You have to rotate the image in-place, which means you have to modify the input 2D matrix directly. DO NOT allocate`
	`6`	`+another 2D matrix and do the rotation.`
	`7`	`+`
	`8`	`+Example 1:`
	`9`	`+`
	`10`	`+> Input: matrix = [[1,2,3],[4,5,6],[7,8,9]]`
	`11`	`+>`
	`12`	`+> Output: [[7,4,1],[8,5,2],[9,6,3]]`
	`13`	`+`
	`14`	`+Example 2:`
	`15`	`+`
	`16`	`+> Input: matrix = [[5,1,9,11],[2,4,8,10],[13,3,6,7],[15,14,12,16]]`
	`17`	`+>`
	`18`	`+> Output: [[15,13,2,5],[14,3,4,1],[12,6,8,9],[16,7,10,11]]`
	`19`	`+`
	`20`	`+Constraints:`
	`21`	`+`
	`22`	+- `n == matrix.length == matrix[i].length`
	`23`	+- `1 <= n <= 20`
	`24`	+- `-1000 <= matrix[i][j] <= 1000`

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	`1`	`+package com.schmoczer.leetcode._0048`
	`2`	`+`
	`3`	`+class RotateImage {`
	`4`	`+ // Runtime 0ms Beats 100.00%`
	`5`	`+ fun rotate(matrix: Array<IntArray>) {`
	`6`	`+ var i = 0`
	`7`	`+ while (i < matrix.size - 1 - i) {`
	`8`	`+ val width = matrix.size - i - 1`
	`9`	`+ for (j in i until width) {`
	`10`	`+ val up = matrix[i][j]`
	`11`	`+ val right = matrix[j][width]`
	`12`	`+ val down = matrix[width][matrix.size - 1 - j]`
	`13`	`+ val left = matrix[matrix.size - 1 - j][i]`
	`14`	`+ matrix[j][width] = up`
	`15`	`+ matrix[width][matrix.size - 1 - j] = right`
	`16`	`+ matrix[matrix.size - 1 - j][i] = down`
	`17`	`+ matrix[i][j] = left`
	`18`	`+ }`
	`19`	`+ i++`
	`20`	`+ }`
	`21`	`+ }`
	`22`	`+}`
	`23`	`+`
	`24`	`+// width = 4 - 0 = 4`
	`25`	`+// i = 0, j = 0, right should be: (0, 3)`
	`26`	`+// first: j = 0, second: width - 1 = 3?`
	`27`	`+// down should be: (3, 3)`
	`28`	`+// row: width - 1 = 3, column: width - 1 - j = 3`
	`29`	`+// left should be: (3, 0)`
	`30`	`+//`
	`31`	`+// i = 0, j = 1, right should be: (1, 3)`
	`32`	`+// first: j = 1, second: widht - 1 = 3`
	`33`	`+// down should be (3, 2)`
	`34`	`+// row: width - 1, column: width - 1 - j = 2`
	`35`	`+// left should be (2, 0)`
	`36`	`+//`
	`37`	`+// i = 0, j = 2, right should (2, 3)`
	`38`	`+//`
	`39`	`+// width = 4 - 1 = 3`
	`40`	`+// i = 1, j = 1, right should be (1, 2)`
	`41`	`+// row: j = 1, column: width - 1 = 2`
	`42`	`+// down should be (2, 2)`
	`43`	`+// row: width - 1 = 2, column: width - 1 - j =`
	`44`	`+// left should be (2, 1)`

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	`1`	`+package com.schmoczer.leetcode._0048`
	`2`	`+`
	`3`	`+import org.junit.jupiter.api.BeforeEach`
	`4`	`+import kotlin.test.Test`
	`5`	`+import kotlin.test.assertContentEquals`
	`6`	`+`
	`7`	`+class RotateImageTest {`
	`8`	`+ private lateinit var sut: RotateImage`
	`9`	`+`
	`10`	`+ @BeforeEach`
	`11`	`+ fun setUp() {`
	`12`	`+ sut = RotateImage()`
	`13`	`+ }`
	`14`	`+`
	`15`	`+ @Test`
	`16`	+ fun `rotate 3x3 matrix`() {
	`17`	`+ val input = arrayOf(intArrayOf(1, 2, 3), intArrayOf(4, 5, 6), intArrayOf(7, 8, 9))`
	`18`	`+ val expected = arrayOf(intArrayOf(7, 4, 1), intArrayOf(8, 5, 2), intArrayOf(9, 6, 3))`
	`19`	`+`
	`20`	`+ sut.rotate(input)`
	`21`	`+`
	`22`	`+ for (i in 0 until expected.size) {`
	`23`	`+ assertContentEquals(expected[i], input[i])`
	`24`	`+ }`
	`25`	`+ }`
	`26`	`+`
	`27`	`+ @Test`
	`28`	+ fun `rotate 4x4 matrix`() {
	`29`	`+ val input = arrayOf(intArrayOf(5, 1, 9, 11), intArrayOf(2, 4, 8, 10), intArrayOf(13, 3, 6, 7), intArrayOf(15, 14, 12, 16))`
	`30`	`+ val expected = arrayOf(intArrayOf(15, 13, 2, 5), intArrayOf(14, 3, 4, 1), intArrayOf(12, 6, 8, 9), intArrayOf(16, 7, 10, 11))`
	`31`	`+`
	`32`	`+ sut.rotate(input)`
	`33`	`+`
	`34`	`+ for (i in 0 until expected.size) {`
	`35`	`+ assertContentEquals(expected[i], input[i])`
	`36`	`+ }`
	`37`	`+ }`
	`38`	`+}`

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