leetcode/0064-minimum-path-sum.py at master · rustykitty/leetcode · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
"""
64. Minimum Path Sum

Submitted: March 19, 2026

Runtime: 46 ms (beats 9.88%)
Memory: 37.36 MB (beats 6.12%)
"""

import functools

class Solution:
    def minPathSum(self, grid: List[List[int]]) -> int:
        self.grid = grid
        self.m = len(grid)
        self.n = len(grid[0])
        return self._minPathSum(0, 0)

    @functools.cache
    def _minPathSum(self, i, j):
        grid = self.grid
        m = self.m
        n = self.n

        if i == m - 1 and j == n - 1:
            return grid[i][j]
        if i >= m or j >= n:
            return float("inf") # not possible
        if i == m - 1:
            return self._minPathSum(i, j + 1) + grid[i][j]
        if j == n - 1:
            return self._minPathSum(i + 1, j) + grid[i][j]
        return min(
            self._minPathSum(i + 1, j),
            self._minPathSum(i, j + 1)
        ) + grid[i][j]