1.map,TreeMap(底层红黑树,保证key有序排列)
C++
map<int,int> mp;
mp[1]=2;
if(mp.count(1)==0)
for(auto x:mp)
{
cout<<x.first<<" "<<x.second<<endl;
}
mp.erase(1)
mp.size()
Java
TreeMap<Integer,Integer> mp=new TreeMap<>();
mp.put(1,2);
mp.put(1,mp.getOrDefault(1,0)+2);
if(mp.containsKey(1))
for(Map.Entry<Integer,Integer> x:mp.entrySet())
{
System.out.println(x.getKey()+" "+x.getValue());
}
mp.remove(1)
mp.size()
2.unordered_map,HashMap
C++
unordered_map<int,int> mp;
mp[1]=2;
if(mp.count(1)==0)
for(auto x:mp)
{
cout<<x.first<<" "<<x.second<<endl;
}
mp.erase(1)
mp.size()
Java
HashMap<Integer,Integer> mp=new HashMap<>();
mp.put(1,2);
if(mp.containsKey(1