规范格式

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

@@ -0,0 +1,26 @@
+package leetcode
+
+func rotate(matrix [][]int) {
+	row := len(matrix)
+	if row <= 0 {
+		return
+	}
+	column := len(matrix[0])
+	// 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
+		}
+	}
+	// 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
+		}
+	}
+}

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

@@ -0,0 +1,50 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question48 struct {
+	para48
+	ans48
+}
+
+// para 是参数
+// one 代表第一个参数
+type para48 struct {
+	s [][]int
+}
+
+// ans 是答案
+// one 代表第一个答案
+type ans48 struct {
+	s [][]int
+}
+
+func Test_Problem48(t *testing.T) {
+
+	qs := []question48{
+
+		question48{
+			para48{[][]int{[]int{1, 2, 3}, []int{4, 5, 6}, []int{7, 8, 9}}},
+			ans48{[][]int{[]int{7, 4, 1}, []int{8, 5, 2}, []int{9, 6, 3}}},
+		},
+
+		question48{
+			para48{[][]int{[]int{5, 1, 9, 11}, []int{2, 4, 8, 10}, []int{13, 3, 6, 7}, []int{15, 14, 12, 16}}},
+			ans48{[][]int{[]int{15, 13, 2, 5}, []int{14, 3, 4, 1}, []int{12, 6, 8, 9}, []int{16, 7, 10, 11}}},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 48------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans48, q.para48
+		fmt.Printf("【input】:%v \n", p)
+		rotate(p.s)
+		fmt.Printf("【output】:%v\n", p)
+		fmt.Printf("\n")
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/0048.Rotate-Image/README.md

@@ -0,0 +1,91 @@
+# [48. Rotate Image](https://leetcode.com/problems/rotate-image/)
+
+## 题目
+
+You are given an *n* x *n* 2D matrix representing an image.
+
+Rotate the image by 90 degrees (clockwise).
+
+**Note:**
+
+You have to rotate the image **[in-place](https://en.wikipedia.org/wiki/In-place_algorithm)**, which means you have to modify the input 2D matrix directly. **DO NOT** allocate another 2D matrix and do the rotation.
+
+**Example 1:**
+
+
+    Given input matrix = 
+    [
+      [1,2,3],
+      [4,5,6],
+      [7,8,9]
+    ],
+    
+    rotate the input matrix in-place such that it becomes:
+    [
+      [7,4,1],
+      [8,5,2],
+      [9,6,3]
+    ]
+
+
+**Example 2:**
+
+
+    Given input matrix =
+    [
+      [ 5, 1, 9,11],
+      [ 2, 4, 8,10],
+      [13, 3, 6, 7],
+      [15,14,12,16]
+    ], 
+    
+    rotate the input matrix in-place such that it becomes:
+    [
+      [15,13, 2, 5],
+      [14, 3, 4, 1],
+      [12, 6, 8, 9],
+      [16, 7,10,11]
+    ]
+
+
+## 题目大意
+
+给定一个 n × n 的二维矩阵表示一个图像。将图像顺时针旋转 90 度。说明：你必须在原地旋转图像，这意味着你需要直接修改输入的二维矩阵。请不要使用另一个矩阵来旋转图像。
+
+
+## 解题思路
+
+- 给出一个二维数组，要求顺时针旋转 90 度。
+- 这一题比较简单，按照题意做就可以。这里给出 2 种旋转方法的实现，顺时针旋转和逆时针旋转。
+
+```c
+    /*
+     * clockwise rotate 顺时针旋转
+     * first reverse up to down, then swap the symmetry 
+     * 1 2 3     7 8 9     7 4 1
+     * 4 5 6  => 4 5 6  => 8 5 2
+     * 7 8 9     1 2 3     9 6 3
+    */
+    void rotate(vector<vector<int> > &matrix) {
+        reverse(matrix.begin(), matrix.end());
+        for (int i = 0; i < matrix.size(); ++i) {
+            for (int j = i + 1; j < matrix[i].size(); ++j)
+                swap(matrix[i][j], matrix[j][i]);
+        }
+    }
+    
+    /*
+     * anticlockwise rotate 逆时针旋转
+     * first reverse left to right, then swap the symmetry
+     * 1 2 3     3 2 1     3 6 9
+     * 4 5 6  => 6 5 4  => 2 5 8
+     * 7 8 9     9 8 7     1 4 7
+    */
+    void anti_rotate(vector<vector<int> > &matrix) {
+        for (auto vi : matrix) reverse(vi.begin(), vi.end());
+        for (int i = 0; i < matrix.size(); ++i) {
+            for (int j = i + 1; j < matrix[i].size(); ++j)
+                swap(matrix[i][j], matrix[j][i]);
+        }
+    }
+```