Coin Collector - Approach

First, find all SCCs using Kosaraju or Tarjan. Compress the graph: each SCC becomes one node with total coins equal to the sum of all coins in that SCC. Build the condensation DAG with edges between components. Run DP on this DAG: dp[v] represents the maximum coins you can collect starting from component $v$.

Base case: If component $v$ has no outgoing edges, dp[v] = coins[v]. Transition: dp[v] = coins[v] + max(dp[u]) for all edges $v \to u$ in the condensation graph. Process nodes in reverse topological order so each successor's DP value is ready before you need it.