SRM 416 DIV2 Level.1
長いな・・・。
もっとスマートに書けるはず。
public class MostCommonLetters { public String listMostCommon(String[] text) { Dictionary<char, int> dic = new Dictionary<char, int>(); foreach (String s in text) { foreach (Char c in s) { if (c != ' ') { if (dic.ContainsKey(c)) { dic[c]++; } else { dic[c] = 0; } } } } int max = 0; foreach (int i in dic.Values) { if (i > max) { max = i; } } String ret = ""; for (char i = 'a'; i <= 'z'; i++) { if (dic.ContainsKey(i)) { if (dic[i] == max) { ret += i; } } } return ret; } }