Minimum Falling Path Sum II Python Solution

lcpy gen -n 1289   # by problem number
lcpy gen -s minimum_falling_path_sum_ii   # by problem name

Input: grid = [[1,2,3],[4,5,6],[7,8,9]]
Output: 13
Explanation:
The possible falling paths are:
[1,5,9], [1,5,7], [1,6,7], [1,6,8],
[2,4,8], [2,4,9], [2,6,7], [2,6,8],
[3,4,8], [3,4,9], [3,5,7], [3,5,9]
The falling path with the smallest sum is [1,5,7], so the answer is 13.

Input: grid = [[7]]
Output: 7

class Solution:
    def min_falling_path_sum(self, grid: list[list[int]]) -> int:
        n = len(grid)
        dp = grid[0][:]
        for i in range(1, n):
            first, second = sorted(dp)[:2]
            dp = [grid[i][j] + (second if dp[j] == first else first) for j in range(n)]
        return min(dp)