HardNo. 2065

Maximum Path Quality of a Graph — LeetCode 2065 Python Solution

Topics
Graph, Array, Backtracking
Reading time
5 min

The problem

There is an undirected graph with n nodes numbered from 0 to n - 1 (inclusive). You are given a 0-indexed integer array values where values[i] is the value of the ith node.

Example

Input
values = [0,32,10,43], edges = [[0,1,10],[1,2,15],[0,3,10]], maxTime = 49
Output
75
Explanation
One possible path is 0 -> 1 -> 0 -> 3 -> 0. The total time taken is 10 + 10 + 10 + 10 = 40 <= 49.

Python solution

PythonSolution
class Solution:
    def maximalPathQuality(
        self, values: List[int], edges: List[List[int]], maxTime: int
    ) -> int:
        def dfs(u: int, cost: int, value: int):
            if u == 0:
                nonlocal ans
                ans = max(ans, value)
            for v, t in g[u]:
                if cost + t <= maxTime:
                    if vis[v]:
                        dfs(v, cost + t, value)
                    else:
                        vis[v] = True
                        dfs(v, cost + t, value + values[v])
                        vis[v] = False

        n = len(values)
        g = [[] for _ in range(n)]
        for u, v, t in edges:
            g[u].append((v, t))
            g[v].append((u, t))
        vis = [False] * n
        vis[0] = True
        ans = 0
        dfs(0, 0, values[0])
        return ans

Complexity

Time
O(n + m + 4fracmaxTimemin(time_j))
Space · auxiliary
O(n + m + fracmaxTimemin(time_j))

Pattern: Backtracking

Build candidates one choice at a time and abandon a branch the moment it cannot work. LeetCode 2065. Maximum Path Quality of a Graph is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Backtracking.

The backtracking guide has the Python template for the pattern and the 105 LeetCode problems that use it.

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Frequently asked questions

How hard is LeetCode 2065. Maximum Path Quality of a Graph?

LeetCode 2065. Maximum Path Quality of a Graph is rated Hard on LeetCode.

What is the time complexity of LeetCode 2065. Maximum Path Quality of a Graph?

The Python solution on this page runs in O(n + m + 4fracmaxTimemin(time_j)).

What is the space complexity of LeetCode 2065. Maximum Path Quality of a Graph?

The Python solution on this page uses O(n + m + fracmaxTimemin(time_j)) auxiliary space.

What topics does LeetCode 2065. Maximum Path Quality of a Graph cover?

LeetCode 2065. Maximum Path Quality of a Graph is tagged Graph, Array and Backtracking on LeetCode.

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