12周刷题大作战

class  {
    public int numRabbits(int[] answers) {
        if(answers.length == 0){
            return 0;
        }
        
        Map<Integer, Integer> map = new HashMap<>();
        for(int i = 0; i < answers.length; i++){
            if(map.containsKey(answers[i]+1)){
                map.put(answers[i]+1, map.get(answers[i]+1)+1);
            }else{
                map.put(answers[i]+1, 1);
            }
        }
        
        int result = 0;
        int key = 0;
        int value = 0;
        for(Map.Entry<Integer, Integer> entry : map.entrySet()){
            key = entry.getKey();
            value = entry.getValue();
            if (value%key != 0){
                result +=  key*(value/key+1);
            }else{
                result += value;
            }                
        }
        return result;   
    }
}