Some of my test cases are failing due to Wrong Answer. Could anyone please let me know where I am going wrong

`

static Integer findParent(int node, List parent){ if(node == parent.get(node)){ return node; }

    return parent.set(parent.get(node), findParent(parent.get(node), parent));
}

static void union(int u, int v, List<Integer> parent, List<Integer> rank){
    int pu = findParent(u, parent);
    int pv = findParent(v, parent);

    if(rank.get(pu) > rank.get(pv)) {
        parent.set(pv, pu);
    }else if(rank.get(pu) < rank.get(pv)) {
        parent.set(pu, pv);
    }else {
        parent.set(pv, pu);
        rank.set(pu, rank.get(pu) + 1);
    }
}

public static long roadsAndLibraries(int n, int c_lib, int c_road, List<List<Integer>> cities) {

    List<Integer> parent = new ArrayList<>();
    List<Integer> rank = new ArrayList<>();
    HashMap<Integer, Integer> freqMap = new HashMap<>();
    long result = 0;

    for(int i = 0; i <= n; i++){
        parent.add(i);
        rank.add(0);
    }

    for(int i = 0; i< cities.size(); i++){
        int u = cities.get(i).get(0);
        int v = cities.get(i).get(1);
        union(u, v, parent, rank);
    }

    for(int i = 1; i <= n; i++){
        Integer fp = findParent(i, parent);
        freqMap.put(fp, freqMap.getOrDefault(fp, 0) + 1);
    }

    for(Integer val: freqMap.values()){
        result += Math.min((long)val * c_lib, ((long)(val - 1) * c_road) + c_lib);
    }

    return result;
}

}`