没啥思路

 

 

class Solution:
    def findDiagonalOrder(self, mat: List[List[int]]) -> List[int]:
        m=len(mat)
        n=len(mat[0])
        ret=[]
        if len(mat)==0:
            return ret
        count=0
        #m+n-1是对角线总数
        while count<m+n-1:
            #x和y的和刚好是count数
            #偶数为右上走
            if count%2==0:
                x=count if(count<m)else (m-1)
                y=count-x
                while(x>=0 and y<=n-1):
                    ret.append(mat[x][y])
                    x-=1
                    y+=1
            #奇数左下走
            else:
                y=count if(count<n)else(n-1)
                x=count-y
                while(x<=m-1 and y>=0):
                    ret.append(mat[x][y])
                    x+=1
                    y-=1
            count+=1
        return ret