CODEWITHSUNDEEP
javalistdictionaryarraylisthashmap
nadav ben simon
nadav ben simon

Reputation: 11

why i am getting duplicates in my list after using containsKey method

i am using hashmap to validate that key dosent exist in the map and adding the key to a list i am using containsKey to prevent duplicate but its adding duplicate to my list

 private static  void makeList(int n,ArrayList<Integer> minimum ,HashMap<Integer,Integer> ugly) {
        for(int i=1; minimum.size() < n; ++i) {
           
            if(!ugly.containsKey(2*i)); {
            minimum.add(2*i);
            ugly.put(2*i,2*i );
            }
            int m3=3*i; 
            if(!ugly.containsKey(3*i)){
            minimum.add(3*i);
             ugly.put(3*i,3*i);   
            }
            int m5=5*i;
            if(!ugly.containsKey(m5)){
           minimum.add(m5);
           ugly.put(m5,m5);
            }
            
            
        }
            
    }

Upvotes: 0

Views: 87

Answers (2)

Oleg Cherednik
Oleg Cherednik

Reputation: 18245

Be simple and it clear the code.

private static  void makeList(int n, List<Integer> minimum, Map<Integer,Integer> ugly) {
    for (int i = 1; minimum.size() < n; i++)
        for (int j : Arrays.asList(2, 3, 5))
            if(ugly.put(i * j, i * j) == null)
                minimum.add(i * j);
}

P.S. Why don't you use Set<Integer> instead of Map<Integer, Integer> with key == value?

Upvotes: 0

Deviprasad Sharma
Deviprasad Sharma

Reputation: 536

I see you gave semicolon ; after if() condition

just remove that and try

 private static  void makeList(int n,ArrayList<Integer> minimum ,HashMap<Integer,Integer> ugly) {
        for(int i=1; minimum.size() < n; ++i) {
           
            if(!ugly.containsKey(2*i)) { //<-edited part, removed semicolon
            minimum.add(2*i);
            ugly.put(2*i,2*i );
            }
            int m3=3*i; 
            if(!ugly.containsKey(3*i)){
            minimum.add(3*i);
             ugly.put(3*i,3*i);   
            }
            int m5=5*i;
            if(!ugly.containsKey(m5)){
           minimum.add(m5);
           ugly.put(m5,m5);
            }
            
            
        }

Upvotes: 2

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