Articulation Points
in Undirected Graphs

function findArticulationPoints(V, adj) {
  let timer = 0;
  const tin = new Array(V).fill(-1);
  const low = new Array(V).fill(-1);
  const visited = new Array(V).fill(false);
  const isArticulation = new Array(V).fill(false);

  function dfs(u, parent) {
    visited[u] = true;
    tin[u] = low[u] = timer++;
    let children = 0;

    for (const v of adj[u]) {
      if (v === parent) continue;
      if (visited[v]) {
        low[u] = Math.min(low[u], tin[v]);
      } else {
        dfs(v, u);
        low[u] = Math.min(low[u], low[v]);
        if (low[v] >= tin[u] && parent !== -1) {
          isArticulation[u] = true;
        }
        children++;
      }
    }

    if (parent === -1 && children > 1) {
      isArticulation[u] = true;
    }
  }

  for (let i = 0; i < V; i++) {
    if (!visited[i]) {
      dfs(i, -1);
    }
  }

  const result = [];
  for (let i = 0; i < V; i++) {
    if (isArticulation[i]) result.push(i);
  }
  return result;
}

const graph = {
  0: [1, 2],
  1: [0, 2],
  2: [0, 1, 3],
  3: [2, 4, 5],
  4: [3],
  5: [3]
};

const V = Object.keys(graph).length;
console.log("Articulation Points:", findArticulationPoints(V, graph));