public class Solution
extends Object
1857 - Largest Color Value in a Directed Graph\.
Hard
There is a **directed graph** of `n` colored nodes and `m` edges. The nodes are numbered from `0` to `n - 1`.
You are given a string `colors` where `colors[i]` is a lowercase English letter representing the **color** of the ith node in this graph ( **0-indexed** ). You are also given a 2D array `edges` where edges[j] = [aj, bj] indicates that there is a **directed edge** from node aj to node bj.
A valid **path** in the graph is a sequence of nodes x1 -> x2 -> x3 -> ... -> xk such that there is a directed edge from xi to xi+1 for every `1 <= i < k`. The **color value** of the path is the number of nodes that are colored the **most frequently** occurring color along that path.
Return _the **largest color value** of any valid path in the given graph, or_ `-1` _if the graph contains a cycle_.
**Example 1:**
**Input:** colors = "abaca", edges = \[\[0,1],[0,2],[2,3],[3,4]]
**Output:** 3
**Explanation:** The path 0 -> 2 -> 3 -> 4 contains 3 nodes that are colored `"a" (red in the above image)`.
**Example 2:**
**Input:** colors = "a", edges = \[\[0,0]]
**Output:** -1
**Explanation:** There is a cycle from 0 to 0.
**Constraints:**
* `n == colors.length`
* `m == edges.length`
* 1 <= n <= 105
* 0 <= m <= 105
* `colors` consists of lowercase English letters.
* 0 <= aj, bj < n