Count occurance of string in an array

Question

Please help me find a way to solve this efficiently.

Problem statement: Find individual occurance of every character in an array.

Input:

[a,a,a,b,b,b,c,c,c,c,a]

Output:

a: 4
b: 3
c: 4

Answer 1

You can use hashmap to solve this, here is the function for implementing it,

Map<String,Integer> hm = new HashMap();
for(String x:array){
    if(!hm.containsKey(x)){
        hm.put(x,1);
    }else{
        hm.put(x, hm.get(x)+1);
    }
}
System.out.println(hm);