54. 螺旋矩阵
给你一个 m
行 n
列的矩阵 matrix
,请按照 顺时针螺旋顺序 ,返回矩阵中的所有元素。
示例 2:
输入:matrix = [[1,2,3,4],[5,6,7,8],[9,10,11,12]]
输出:[1,2,3,4,8,12,11,10,9,5,6,7]
//时间Omn,空间Omn
func spiralOrder(matrix [][]int) []int {
if len(matrix) == 0 {
return []int{}
}
res := []int{}
top, bottom := 0, len(matrix) -1
left, right := 0, len(matrix[0]) -1
for top <= bottom && left <= right {
for i := left; i <= right; i++ {
res = append(res, matrix[top][i])
}
top++
for i := top; i <= bottom; i++ {
res = append(res, matrix[i][right])
}
right--
if top > bottom || left > right {
break
}
for i := right; i >= left; i-- { //注意:这里i--,也变成bot相反
res = append(res, matrix[bottom][i])
}
bottom--
for i := bottom; i >= top; i-- {
res = append(res,matrix[i][left])
}
left++
}
return res
}