Maximum Vacation Days — LeetCode 568 Python Solution

The problem

LeetCode wants to give one of its best employees the option to travel among n cities to collect algorithm problems. But all work and no play makes Jack a dull boy, you could take vacations in some particular cities and weeks.

Example

Input

flights = [[0,1,1],[1,0,1],[1,1,0]], days = [[1,3,1],[6,0,3],[3,3,3]]

Output

12

Explanation

One of the best strategies is:

Python solution

class Solution:
    def maxVacationDays(self, flights: List[List[int]], days: List[List[int]]) -> int:
        n = len(flights)
        K = len(days[0])
        f = [[-inf] * n for _ in range(K + 1)]
        f[0][0] = 0
        for k in range(1, K + 1):
            for j in range(n):
                f[k][j] = f[k - 1][j]
                for i in range(n):
                    if flights[i][j]:
                        f[k][j] = max(f[k][j], f[k - 1][i])
                f[k][j] += days[j][k - 1]
        return max(f[-1][j] for j in range(n))

Complexity

Pattern: Matrix and Grid

Treat a 2-D grid as a graph whose neighbours are the four adjacent cells. LeetCode 568. Maximum Vacation Days is filed here because LeetCode tags it Matrix, which is the vocabulary this hub collects.

The matrix and grid guide has the Python template for the pattern and the 216 LeetCode problems that use it.

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