Disjoint set union (DSU)

DisJoint set union : It is a technique in graphs used for grouping problems

    There are two functions  used (find and union )

     Find: find parent;

     Union: merge two groups with a rule;

  public int find(int x,int[] par){
       if(par[x]==x){
           return x;
       }
       par[x]=find(par[x],par);
       return par[x];
        
    }
    public void union(int x,int y,int[] par){
        int px = find(x,par);
        int py = find(y,par);
        if(px!=py){
            if(px<py){
                    par[py]=px;
            }else{
                    par[px]=py;            }
        } 
    }

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