UNION MAKE SET FIND SET

 

void make_set(int v) {

    parent[v] = v;

}

int find_set(int v) {

    if (v == parent[v])

        return v;

    return find_set(parent[v]);

}

void union_sets(int a, int b) {

    a = find_set(a);

    b = find_set(b);

    if (a != b)

        parent[b] = a;

}

There are two ways to improve it: 

1. Path Compression

2. Union by Rank