Number of Connected Components in an Undirected Graph

Description

null

Solution(javascript)

/**
 * @param {number} n
 * @param {number[][]} edges
 * @return {number}
 */
var countComponents = function(n, edges) {
    const parent = new Array(n).fill(0).map((x, index) => index)
    const root = (a) => {
        while(a !== parent[a]) {
            parent[a] = parent[parent[a]]
            a = parent[a]
        }
        return a
    }
    let size = n
    const union = (a, b) => {
        const rootA = root(a)
        const rootB = root(b)
        if(rootA !== rootB) {
            size -= 1
            parent[rootA] = rootB
        }
    }
    edges.forEach(([a, b]) => {
        union(a,b)
    })
    return size
};