题目：
题解：
class Solution:
def minPathSum(self, grid: List[List[int]]) -> int:
if not grid or not grid[0]:
return 0
rows, columns = len(grid), len(grid[0])
dp = [[0] * columns for _ in range(rows)]
dp[0][0] = grid[0][0]
for i in range(1, rows):
dp[i][0] = dp[i - 1][0] + grid[i][0]
for j in range(1, columns):
dp[0][j] = dp[0][j - 1] + grid[0][j]
for i in range(1, rows):
for j in range(1, columns):
dp[i][j] = min(dp[i - 1][j], dp[i][j - 1]) + grid[i][j]
return dp[rows - 1][columns - 1]
