题目：

题解：

func findDiagonalOrder(mat [][]int) []int {m, n := len(mat), len(mat[0])ans := make([]int, 0, m*n)for i := 0; i < m+n-1; i++ {if i%2 == 1 {x := max(i-n+1, 0)y := min(i, n-1)for x < m && y >= 0 {ans = append(ans, mat[x][y])x++y--}} else {x := min(i, m-1)y := max(i-m+1, 0)for x >= 0 && y < n {ans = append(ans, mat[x][y])x--y++}}}return ans
}func min(a, b int) int {if a > b {return b}return a
}func max(a, b int) int {if b > a {return b}return a
}