Disjoint Set Union Data Structure

#include <vector>
#include <numeric>
using namespace std;
class DisjointSetUnion {
private:
    vector<int> parents;
    vector<int> ranks;
public:
    DisjointSetUnion(int numberOfSets) {
        this->parents = vector<int>(numberOfSets);
        this->ranks = vector<int>(numberOfSets);
        // every elements starts as its own parent -- and representative
        iota(this->parents.begin(), this->parents.end(), 0);
    }
    int find(int u) {
        // find the root
        int root = u;
        while (this->parents[root] != root) { root = this->parents[root]; }
        // compress paths
        while (this->parents[u] != root) {
            int tmp = this->parents[u];
            this->parents[u] = root;
            u = tmp;
        }
        return root;
    }
    void unite(int u, int v) {
        u = this->find(u);
        v = this->find(v);
        // u and v are already in the same set
        if (u == v) { return; }
        // union by rank -> the root with greater rank becomes the new root
        if (this->ranks[u] == this->ranks[v]) {
            this->parents[u] = v;
            this->ranks[v]++;
        } else if (this->ranks[u] < this->ranks[v]) {
            this->parents[u] = v;
        } else if (this->ranks[u] > this->ranks[v]){
            this->parents[v] = u;
        }
    }
};