Strongly Connected Components
Using Kosaraju's Algorithm

function kosarajuSCC(V, adj) {
  const visited = new Array(V).fill(false);
  const stack = [];

  function dfs(v) {
    visited[v] = true;
    for (let nei of adj[v] || []) {
      if (!visited[nei]) dfs(nei);
    }
    stack.push(v);
  }

  for (let i = 0; i < V; i++) {
    if (!visited[i]) dfs(i);
  }

  const transpose = Array.from({ length: V }, () => []);
  for (let u = 0; u < V; u++) {
    for (let v of adj[u] || []) {
      transpose[v].push(u);
    }
  }

  visited.fill(false);
  let count = 0;

  function reverseDFS(v) {
    visited[v] = true;
    for (let nei of transpose[v]) {
      if (!visited[nei]) reverseDFS(nei);
    }
  }

  while (stack.length > 0) {
    const node = stack.pop();
    if (!visited[node]) {
      reverseDFS(node);
      count++;
    }
  }

  return count;
}

// Example usage
const graph = {
  0: [1],
  1: [2],
  2: [0],
  3: [4]
};

console.log("Number of SCCs:", kosarajuSCC(5, graph)); // Output: 2