A.底層數(shù)據(jù)結(jié)構(gòu)是紅黑樹 B.元素可重復(fù) C.可以通過自然排序?qū)υ剡M(jìn)行排序 D.可以通過比較器排序?qū)υ剡M(jìn)行排序
A.if(map.contains(ch[i])){map.put(ch[i],map.get(ch[i])+1);}else{map.put(ch[i],1);} B.if(map.contains(ch[i])){map.put(ch[i],(Integer)map.get(ch[i])+1);}else{map.put(ch[i],1);} C.if(map.containsKey(ch[i])){map.put(ch[i],(int)map.get(ch[i])+1);}else{map.put(ch[i],1);} D.if(map.containsKey(ch[i])){map.put(ch[i],(Integer)map.get(ch[i])+1);}else{map.put(ch[i],1);}
A.其元素?zé)o序,且不可重復(fù) B.有順序,元素可以重復(fù) C.底層用數(shù)組實(shí)現(xiàn)的 D.其元素是鍵值對方式