Merge pull request halfrost#133 from NovaHe/fix/48

fix/48: clean up code

Author: halfrost

leetcode/0048.Rotate-Image/48. Rotate Image.go

@@ -1,26 +1,17 @@
 package leetcode
 
 func rotate(matrix [][]int) {
-	row := len(matrix)
-	if row <= 0 {
-		return
-	}
-	column := len(matrix[0])
+	length := len(matrix)
 	// rotate by diagonal 对角线变换
-	for i := 0; i < row; i++ {
-		for j := i + 1; j < column; j++ {
-			tmp := matrix[i][j]
-			matrix[i][j] = matrix[j][i]
-			matrix[j][i] = tmp
+	for i := 0; i < length; i++ {
+		for j := i + 1; j < length; j++ {
+			matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]
 		}
 	}
 	// rotate by vertical centerline 竖直轴对称翻转
-	halfColumn := column / 2
-	for i := 0; i < row; i++ {
-		for j := 0; j < halfColumn; j++ {
-			tmp := matrix[i][j]
-			matrix[i][j] = matrix[i][column-j-1]
-			matrix[i][column-j-1] = tmp
+	for i := 0; i < length; i++ {
+		for j := 0; j < length/2; j++ {
+			matrix[i][j], matrix[i][length-j-1] = matrix[i][length-j-1], matrix[i][j]
 		}
 	}
 }

website/content/ChapterFour/0001~0099/0048.Rotate-Image.md

@@ -97,35 +97,23 @@ You have to rotate the image **[in-place](https://en.wikipedia.org/wiki/In-plac
 ## 代码
 
 ```go
-
 package leetcode
 
 func rotate(matrix [][]int) {
-	row := len(matrix)
-	if row <= 0 {
-		return
-	}
-	column := len(matrix[0])
+	length := len(matrix)
 	// rotate by diagonal 对角线变换
-	for i := 0; i < row; i++ {
-		for j := i + 1; j < column; j++ {
-			tmp := matrix[i][j]
-			matrix[i][j] = matrix[j][i]
-			matrix[j][i] = tmp
+	for i := 0; i < length; i++ {
+		for j := i + 1; j < length; j++ {
+			matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]
 		}
 	}
 	// rotate by vertical centerline 竖直轴对称翻转
-	halfColumn := column / 2
-	for i := 0; i < row; i++ {
-		for j := 0; j < halfColumn; j++ {
-			tmp := matrix[i][j]
-			matrix[i][j] = matrix[i][column-j-1]
-			matrix[i][column-j-1] = tmp
+	for i := 0; i < length; i++ {
+		for j := 0; j < length/2; j++ {
+			matrix[i][j], matrix[i][length-j-1] = matrix[i][length-j-1], matrix[i][j]
 		}
 	}
 }
-
-
 ```