You have to paint all the houses such that no two adjacent houses have the same color.
The cost of painting each house with a certain color is represented by an n x 3 cost matrix costs.
For example, costs[0][0] is the cost of painting house 0 with the color red; costs[1][2] is the cost of painting house 1 with color green, and so on.
Return the minimum cost to paint all houses.
There is a directed graph of n nodes with each node labeled from 0 to n - 1. The graph is represented by a 0-indexed 2D integer array graph where graph[i] is an integer array of nodes adjacent to node i, meaning there is an edge from node i to each node in graph[i].
A node is a terminal node if there are no outgoing edges. A node is a safe node if every possible path starting from that node leads to a terminal node (or another safe node).
Return an array containing all the safe nodes of the graph. The answer should be sorted in ascending order.
Example 1:
Input: graph = [[1,2],[2,3],[5],[0],[5],[],[]]
Output: [2,4,5,6]
Explanation: The given graph is shown above.
Nodes 5 and 6 are terminal nodes as there are no outgoing edges from either of them.
Every path starting at nodes 2, 4, 5, and 6 all lead to either node 5 or 6.Example 2:
Input: graph = [[1,2,3,4],[1,2],[3,4],[0,4],[]]
Output: [4]
Explanation: Only node 4 is a terminal node, and every path starting at node 4 leads to node 4.This page combines two classic interview-style prompts: the Paint House dynamic programming problem, where the goal is to minimize total cost without using the same color on adjacent houses, and the eventual safe nodes problem on a directed graph, which is typically solved with reverse graph traversal, topological sorting, or DFS coloring to detect cycles. The examples illustrate how terminal nodes and nodes that only lead to terminal/safe nodes are identified.
