题目描述：

 

 

 

 

 

 方法一：

class Solution:
    def findDiagonalOrder(self, nums: List[List[int]]) -> List[int]:
        a,s,m=[(0,0)],[nums[0][0]],len(nums)
        while a:
            b=[]
            for i,j in a:
                for ii,jj in (i+1,j),(i,j+1):
                    if ii<m and jj<len(nums[ii]) and nums[ii][jj]!=-1:
                        s.append(nums[ii][jj])
                        b.append((ii,jj))
                        nums[ii][jj]=-1
            a=b
        return s

方法二：排序

class Solution:
    def findDiagonalOrder(self, nums: List[List[int]]) -> List[int]:
        ans = []
        for i, l in enumerate(nums):
            for j, n in enumerate(l):
                ans.append((i + j, j, n))
        ans.sort()
        return [a[2] for a in ans]