Union Find Template

union-find-template.js

const parent = Array(rows * cols).fill(0).map((value, index) => index);
const rank = Array(rows * cols).fill(0);

const find = (i) => {
    if (parent[i] !== i) parent[i] = find(parent[i]);

    return parent[i];
};

 const union = (x, y) => {
    const rootx = find(x);
    const rooty = find(y);
   
    if (rootx !== rooty) {
      if (rank[rootx] > rank[rooty]) {
        parent[rooty] = rootx;
      } else if (rank[rootx] < rank[rooty]) {
        parent[rootx] = rooty;
      } else {
        // just use this line if not doing rank
        parent[rooty] = rootx;
        rank[rootx] += 1;
       }
      // these two were now unioned
    }
  };