Most Stones Removed
with Same Row or Column (Graph-Based)

function removeStones(stones) {
  const adj = new Map();

  // Build graph with row/col identifier trick to avoid collisions
  for (const [x, y] of stones) {
    const row = `r${x}`;
    const col = `c${y}`;

    if (!adj.has(row)) adj.set(row, []);
    if (!adj.has(col)) adj.set(col, []);

    adj.get(row).push(col);
    adj.get(col).push(row);
  }

  const visited = new Set();
  let components = 0;

  function dfs(node) {
    visited.add(node);
    for (const neighbor of adj.get(node) || []) {
      if (!visited.has(neighbor)) {
        dfs(neighbor);
      }
    }
  }

  for (const [x, y] of stones) {
    const node = `r${x}`;
    if (!visited.has(node)) {
      dfs(node);
      components++;
    }
  }

  return stones.length - components;
}

console.log(removeStones([[0,0],[0,1],[1,0],[1,2],[2,1],[2,2]])); // Output: 5
console.log(removeStones([[0,0],[0,2],[1,1],[2,0],[2,2]])); // Output: 3
console.log(removeStones([[0,0]])); // Output: 0