给你一个正整数 n ，生成一个包含 1 到 n2 所有元素，且元素按顺时针顺序螺旋排列的 n x n 正方形矩阵 matrix 。
示例 1：
输入：n = 3
输出：[[1,2,3],[8,9,4],[7,6,5]]示例 2：
输入：n = 1
输出：[[1]]提示：
- 1 <= n <= 20
解题：
func generateMatrix(n int) [][]int {
r := make([][]int, n)
for i := 0; i < n; i++ {
r[i] = make([]int, n)
}
k := 1
for i := 0; i < (n+1)/2; i++ {
for j := i; j < n-i; j++ {
r[i][j] = k
k++
}
if n-i-1-i > 0 {
for j := i + 1; j < n-i-1; j++ {
r[j][n-i-1] = k
k++
}
}
if n-i-1-i >= 1 {
for j := n - i - 1; j >= i; j-- {
r[n-i-1][j] = k
k++
}
}
for j := n - i - 2; j > i; j-- {
r[j][i] = k
k++
}
}
return r
}官方解答：
1.模拟
type pair struct{ x, y int }
var dirs = []pair{{0, 1}, {1, 0}, {0, -1}, {-1, 0}} // 右下左上
func generateMatrix(n int) [][]int {
matrix := make([][]int, n)
for i := range matrix {
matrix[i] = make([]int, n)
}
row, col, dirIdx := 0, 0, 0
for i := 1; i <= n*n; i++ {
matrix[row][col] = i
dir := dirs[dirIdx]
if r, c := row+dir.x, col+dir.y; r < 0 || r >= n || c < 0 || c >= n || matrix[r][c] > 0 {
dirIdx = (dirIdx + 1) % 4 // 顺时针旋转至下一个方向
dir = dirs[dirIdx]
}
row += dir.x
col += dir.y
}
return matrix
}2.按层模拟
func generateMatrix(n int) [][]int {
matrix := make([][]int, n)
for i := range matrix {
matrix[i] = make([]int, n)
}
num := 1
left, right, top, bottom := 0, n-1, 0, n-1
for left <= right && top <= bottom {
for column := left; column <= right; column++ {
matrix[top][column] = num
num++
}
for row := top + 1; row <= bottom; row++ {
matrix[row][right] = num
num++
}
if left < right && top < bottom {
for column := right - 1; column > left; column-- {
matrix[bottom][column] = num
num++
}
for row := bottom; row > top; row-- {
matrix[row][left] = num
num++
}
}
left++
right--
top++
bottom--
}
return matrix
}