[Codility] Lesson8. Dominator (C#)

문제: app.codility.com/programmers/lessons/8-leader/dominator/

Dominator coding task - Learn to Code - Codility

 

결과: 91% 다시 풀어야 함.

 

            if (A.Length == 0)
                return -1;
            else if (A.Length == 1)
                return 0;

            Dictionary<int, int> dic = new Dictionary<int, int>();
            for (int i = 0; i < A.Length; i++)
            {
                if (dic.ContainsKey(A[i]))
                {
                    int cnt = 0;
                    dic.TryGetValue(A[i], out cnt);
                    dic[A[i]] = cnt + 1;
                }
                else
                {
                    dic.Add(A[i], 1);
                }
            }

            List<int> listKey = new List<int>(dic.Keys);
            List<int> listVal = new List<int>(dic.Values);
            listVal.Sort();
            int max = listVal[listVal.Count - 1];
            int leader = -1;

            if (max == listVal[listVal.Count - 2])
                return -1;
            else if (max > A.Length / 2)
            {
                for (int i = 0; i < listKey.Count; i++)
                {
                    int key = listKey[i];
                    int val = 0;
                    dic.TryGetValue(key, out val);
                    if (val == max)
                    {
                        leader = key;
                        break;
                    }
                }

                for (int i = 0; i < A.Length; i++)
                {
                    if (A[i] == leader)
                        return i;
                }
            }

            return leader;